Allergy information for: Garlic (Allium sativum)

Name: Garlic
Scientific Name: Allium sativum
Occurrence: Garlic is normally added as a seasoning before cooking but can be eaten raw. It is widely used as an ingredient in foods such as stews, hotpots and breads.

Allergy Information: Garlic allergy is relatively rare although one case of severe symptoms has been reported after eating garlic. The individual suffered exercise induced anaphylaxis and on a subsequent occasion anaphylaxis without exercise.

Supplementary information on Spices Allergy

The term spice contains an endless number of plant-derived ingredients used in the cuisine to refine foods. All parts of the spice plants from seeds, flowers, leaves, barks to rhizome or roots can be used for refinement of foods. In this overview, also celery, sesame and mustard which belong to the category spices, will be briefly touched too, even if detailed descriptions can be found in separate sections. Names, synonyms and biological classification of the most popular spices are given in Table 1.

Few spices are added raw to the dish. Many of them are used in dried or freeze-dried condition, as dill, parsley or celery, which then contain most of the allergic proteins also present in the raw spice. Allergens in pickled spices are unchanged or better conserved than in the dried ones, e.g. in the case of green versus black pepper. Additionally, mechanical grinding of the dried material may destroy some allergens, e.g. in the case of paprika, but still leave a considerable number of allergenic proteins. Roasted spices may keep their potential for allergenicity, as poppy seeds or sesame, the latter often consumed toasted on bread. Spice allergens can, therefore, be expected in raw, toasted, grilled, baked, cooked, tinned, pickled or dried food when eating out or at home, in freshly prepared or fast food.

Symptoms
Spices may produce mild symptoms: itching, swelling, burning at lips, tongue and palate or severe local reactions in and around the mouth: swelling of the throat, flush, breathing problems, stomach indigestion, vomiting, diarrhoea, and systemic reactions such as hayfever, asthma and anaphylactic shock.

How much is too much?
For most spices, the current scientific evidence is unsatisfactory to establish an intake threshold. However, for the spices taken up into the food allergen list of the EU (see below) some data on lowest reactive threshold are available since recently: for dried celery spice 160 mg, sesame 30 mg, and mustard 40 mg. Below, allergic reactions did not occur in the tested patients. It may be considered that thresholds for other spices may be comparably low and, consequently, low-dose challenge trials are recommended.

Related foods (cross reactivity)
In most cases of reported spice allergy, IgE-cross reactions with pollen were reported. Especially birch pollen, and mugwort pollen allergy represents a risk for the development of reactivity to spices. Cross-reactivity to latex has been reported, too. The elicitors are plant proteins that are similar in different plants. Common reactivity is more likely in plants that are botanically closer related (Table 2).

Who, when, how long, and how often?
Spice allergy represents 2% of all food allergy cases. It is rare in children and more prominent in adults. Allergic reactions can be seen as occupational allergy in spice factory workers. Besides allergic reactions also contact eczema may occur. No data are available today on the outgrowth of spice allergy. For yet unknown reasons women have a double risk to develop food allergies including spices.

Diagnosis
Spices are often hidden in the prepared food and not obvious to the consumer. Therefore, a careful recollection of the allergic reactions is the first important step for the diagnosis of this type of allergies. The safest and least invasive procedure for the patient is blood samples, On the other hand, spices may produce false positive results in skin prick or scratch tests through their contents of irritating substances (in particular in pepper, and cayenne.). (For the same reasons skin tests for diagnosis of allergic contact eczema due to spices, may not be sufficiently reliable). Thus, ideally skin tests should be combined with blood samples. Challenges represent a useful tool for the evaluation of the threshold for reactions and for ultimate diagnosis, but has only rarely been applied in spice allergy. Also inhalation challenges with spices have been made, but are infrequent. This is possibly due to the risk for the development of severe side-effects during provocation tests and unfavourable cost assessments.

Avoidance
When diagnosis of spice allergy has been made, absolute avoidance of the spice is recommended. This should include botanically related spices, because they contain similar proteins that with high probability will also act as allergens (see Table 2). Spices are routinely used by cooks in restaurants or private environments in an automated way, and sometimes are handled as kitchen secrets. Therefore, the person in charge of cooking must be advised in advance to prepare the foodstuff on clean dishes without the possibility of contamination with traces of spices. If severe allergic reactions have occurred in the patient before, the recommendations should be even stricter and consumptions in restaurants or of tinned or fast food can no longer be recommended, considering the today's labelling policy.

Labelling of spices was for a long time insufficiently regulated, e.g. was “spice” as a category sufficient for the whole large panel of different ingredients. According to the aim that all ingredients should be labelled regardless of the quantity contained in the finished food, in 2004 a defined list of foods with allergenic potential has been taken up in the EU labelling issues. They are listed in Annex IIIa of Directive 2003/89/EC, to be brought into force by November 25, 2004. Importantly, this list includes celery, mustard and sesame seed which have a well documented allergenic potential. At least for these common spices the option to declare them as ingredients by category will no longer apply. Facing the fact that spices are hidden in foods in low amounts, the new legislation will improve the consumer's situation. However, severe allergic reactions have also been observed to a number of other spices as e.g. poppy (2), coriander, cumin, dill, curry, or saffron. Therefore, complete labelling of spice ingredients should be an ultimate goal.

Table 1.

Spices: Synonyms and biological description.

Spice	Synonym	Biological Description
Allspice	Jamaica pepper, myrtle pepper, pimento, newspice	Unripe and dried fruits
Anise ¹⁾	aniseed	Dried fruit of annual herb
Basil	tomato herb, herb of kings	annual, spicy herb, fresh or dried leaves
Bay Leaf	sweet bay, laurel	Oval, dark-green, dried leaves
Caraway Seed	Cumin	Dried fruit of a biennial herb
Cardamom	green cardamom, greater c., Nepal c.	Dried, unripened fruit
Cayenne	Chili pepper, red pepper	ripened dried pots
Celery ²⁾	Celeriac	dried fruit or root of a biennial (sometimes annual) herb
Chervil	Garden chervil, French parsley	small, low-growing annual
Chives	-	reed-like stems of a perennial, bulbous plant
Cinnamon	Indonesian c., Cassia, Vietnamese c. White cinnamon	Dried inner bark of evergreen trees
Cloves		Dried, unopened flavour buds
Coriander	Cilantro, Chinese or Indian parsley Vietnamese coriander or mint	Dried fruits, fresh leaves and roots leaf of annual herb
Cumin seeds	Cumin Black cumin	dried ripe fruit of the annual herb dried ripe fruit of the annual herb
Curry Powder	-	blend of coriander, turmeric, cumin, nutmeg, onion, and other spices
Dill	Dill seed or dill weed	Annual plant: dried fruit or dried leaves.
Fennel	Sweet cumin	Dried ripe fruit of the annual plant
Garlic	-	Bulb (cloves)
Ginger		dried knobby shaped rhizome (but not root) of perennial herb
Mace	Nutmeg flower	scarlet membrane (arillus) enwrapping the shell of the nutmeg
Marjoram	Sweet marjoram, knotted marjoram	Dried leaves and floral parts of herb
Mustard	-	Seeds from annual herb
Nutmeg	-	Dried, aromatic seed (called “nut”)
Onion	Scallion, shallots (young onion)	single-bulbed, biennial, herbaceous plant
Oregano	"Wild Marjoram", oregan	leaf of the plant
Paprika	Bell pepper, pod pepper, sweet pepper	Fruits are used dried and ground
Parsley	-	dried and fresh leaves and roots of biennial plant
Pepper: black, white, green	-	berries of tropical vine, dried or pickled (green pepper)
Pink Pepper-corns	Baies roses, pepper rosé	berries native to the Island of Reunion

1. Spices with reported allergenicity are underlined.
2. Spices taken up in the Annex IIIa of Directive 2003/89/EC of the European Community guidelines are underlined and bold.

Table 2. The botanical relationships among important spices.

Botanical family	Spices to be avoided
Apiaceae	Anise ¹⁾, caraway seed, celery ²⁾, chervil, coriander, cumin, dill, fennel, parsley
Solanaceae	Cayenne (chilli), paprika
Myrtaceae	Allspice, cloves, mustard
Lamiaceae = Labiatae	Basil, marjoram, oregano, rosemary, sage, savory, thyme
Lauraceaea	Bay leaf, cinnamon
Zingiberaceae	Cardamom, ginger, turmeric
Alliaceae	Chives, garlic, onion
Myristicaceae	Mace, nutmeg
Piperaceae	Black, white, green pepper
Polygonaceae	Vietnamese coriander
Pedaliaceae	Sesame seeds
Canellaceae	White cinnamon
Anacardiaceae	Pink pepper
Papaveraceae	Poppy seeds
Iridicaceae	Saffron
Illiaceae	Star anise
Asteraceae	Tarragon
Orchidaceae	Vanilla

1. Spices with reported allergenicity are underlined.
2. Spices taken up in the Annex IIIa of Directive 2003/89/EC of the European Community guidelines are underlined and bold.

Other Information:
Taxonomic Information: NEWT http://www.ebi.ac.uk/newt/display?search=4682&from=null
Last modified: 18 October 2006

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References (0)

Clinical History

Number of Studies:1-5
Number of Patients:11-20
Symptoms:Kao et al. (2004) [1102] reported that 11/12 patients showed atopic dermatitis, 10/12 allergic rhinitis, 5/12 asthma and 5/12 urticaria.
Pires et al. (2002) [1103] reported a 16-month-old boy who developed urticaria on the face and neck immediately after local contact with raw garlic.
Perez-Pimiento et al. (1999) [1108] reported a patient who experienced three episodes of exercised induced anaphylaxis after eating when no specific food could be identified as allergenic. The individual subsequently presented generalized urticaria and facial angioedema, followed by a feeling of sickness, hypotension, and loss of consciousness, after eating young garlic with eggs and shrimp, but without exercise.
Asero et al. (1998) [1109] reported a patient who suffered systemic urticaria/angioedema after the ingestion of foods containing both raw or cooked garlic. Garlic also caused contact urticaria.
Pastorello et al. (1989) [1164] reported a single patient with rhinitis and diarrhoea on reintroduction of garlic after an elimination diet.

Skin Prick Test

Number of Studies:1-5
Food/Type of allergen:
Kao et al. (2004) [1102] used two concentrations of purified garlic alliin lyase in phosphate buffered saline.
Pires et al. (2002) [1103] used commercial garlic extract (Stallergènes), fresh raw and fresh cooked garlic. Commercial onion extract (Stallergènes) and fresh raw and cooked onion were also used.
Perez-Pimiento et al. (1999) [1108] used commercial pollen extracts. Raw and cooked young garlic and garlic clove were used in prick-prick tests.
Asero et al. (1998) [1109] used commercial extracts of garlic (Dome-Hollister/Stier and Lofarma Allergeni, Milan) and other foods.
Protocol: (controls, definition of positive etc)Histamine dihydrochloride 10 mg/ml and physiological saline were the positive and negative controls. A positive response was defined as a mean wheal diameter at least 3 mm bigger than that seen with saline after 15 min.
Number of Patients:
Kao et al. (2004) [1102] tested 12 patients.
Pires et al. (2002) [1103] tested 1 patient.
Perez-Pimiento et al. (1999) [1108] tested 1 patient.
Asero et al. (1998) [1109] tested 1 patient.
Summary of Results:
Kao et al. (2004) [1102] report that 12/12 patients (and 0 controls) gave positive SPT to 1 × 10^–8 mol/L of purified alliin lyase whereas 58% (7/12) also gave a positive response with the lower concentration of 2 × 10^–9 mol/L.
Pires et al. (2002) [1103] report that skin prick and prick-prick tests were positive with commercial garlic extract (Stallergènes) and fresh raw garlic with a wheal diameter of 15 X 9 mm and 17 X 8 mm, respectively. The prick-prick test was negative with fresh cooked garlic. Skin prick and prick-prick tests were negative with both commercial onion extract (Stallergènes) and fresh raw and cooked onion.
Perez-Pimiento et al. (1999) [1108] report positive SPTs with pollen of grass, trees (Platanus, Ulmus), and weeds (Artemisia, Taraxacum, Parietaria, and Chenopodium). SPTs were also positive to almond, hazelnut, peanut, walnut, sunflower seed, mustard, and Anisakis. In the prick-prick test, raw young garlic produced a wheal of 23 X 14 mm. Heated young garlic and garlic clove gave wheals of 8 X 4 and 10 X 6 mm, respectively.
Asero et al. (1998) [1109] report a strong skin reaction (wheal grade 4+ by comparison with 10 mg/ml histamine) was induced by two commercial garlic extract. No reaction was seen with onion or any other extract tested.

IgE assay (by RAST, CAP etc)

Number of Studies:0
Food/Type of allergen:
Commercial extracts were used with immunoCAP.
IgE protocol:ImmunoCAP
Number of Patients:Kao et al. (2004) [1102] used sera from 15 patients with allergy to garlic in immunoblotting and sera from 12 patients for comparison of CAP, SPT results and symptoms.
Summary of Results:
Kao et al. (2004) [1102] reported that 2/12 patients were class 1 and 10/12 patients class 2 for garlic specific IgE.
Pires et al. (2002) [1103] reported that specific IgE to garlic and onion (Pharmacia CAP System) were negative (< 0.35 kU/l).

Immunoblotting

Immunoblotting separation:
Kao et al. (2004) [1102] made a crude garlic extract (also shallot, Allium ascalonicum, leek, Allium porrum, and onion, Allium cepa) by homogenizing for 6 × 30 seconds, with an interval of 30 seconds in ice-cold 50 mM phosphate buffer, pH 7.5, containing 1 mM PMSF, 1 mM calcium chloride, and 0.1 mM DTT (10 mL of buffer per gram of material). The homogenate was filtered through two layers of gauze and the filtrate centrifuged at 27,000 x g for 15 minutes at 4°C. Trichloroacetic acid was added to the supernatant solution (crude extract) to a final concentration of 20% and after standing for 15 minutes at 4°C, the sample was centrifugated at 12,000g for 15 minutes at 4°C and the pellet vacuum-dried on a SpeedVac (SC110, Savant, Farmingdale, NY). The pelleted material was analyzed by 2-dimensional (2-D) electrophoresis. An immobilized pH gradient of 3–10 on a horizontal electrophoresis system (Multiphor II, Pharmacia) was used for the first dimension. The second dimension used SDS PAGE with a separation gel of 12.5% polyacrylamide under reducing conditions (5% beta-mercaptoethanol).
Asero et al. (1998) [1109] extracted garlic proteins by stirring some cloves overnight at 4° C in 0.15M phosphate-buffered saline (pH 7.2) in the presence of 2% (w/v) polyvinylpolypyrrolidone, 10mM diethyldithiocarbamate, and 2mM ethylenediamine tetraacetic acid disodium salt. Particulate material was removed by centrifugation at 18,000xg for 30 minutes, and the supernatant was dialyzed against distilled water and lyophilized. Twenty micrograms of garlic extract was applied on a running gel (gradient 10% to 20%), and electrophoresis was carried out at 40 mA for 2 hours.
Immunoblotting detection method:
Kao et al. (2004) [1102] transferred proteins on to PVDF membranes (Millipore) by semi-dry blotting. The blotted membranes were then either stained directly with Coomassie Brilliant Blue R-250 or blocked with 1% skimmed milk in Tris-buffered saline, 20 mM Tris/HCl (pH 7.5) with 500 mM NaCl, at room temperature for 1h then incubated overnight at 4°C with patients' sera (pooled serum from patients 1 through 4) diluted 1:10 in Tris-buffered saline containing 1% v/v Tween-20 (TBST) and 1% w/v skimmed milk. After three washes with TBST, the blots were incubated with anti-human-IgE/alkaline phosphatase antibody (1:2000) for 1h at room temperature and development was carried out using a mixture of Nitro Blue Tetrazolium/5-bromo-4-chloroindol-3-yl phosphate toluidinium as substrate.
Asero et al. (1998) [1109] electrophoretically transferred proteins onto a nylon-cellulose membrane (Fluorotrans 0.45 µm; Pall, Milan, Italy). The membrane was saturated with 0.1 mol/L tris-buffered saline and 5% w/v fat-free milk powder and incubated with patient's serum after washings. Bound specific IgE (before and after adsorption on Protein A; see below) were detected by peroxidase-conjugated anti-human IgE antibodies from goat (1:1000 in saturation buffer) by using an ECL western blotting kit (Amersham, Milan, Italy). To verify if the presence in serum of anti-garlic extract IgG could interfere in the signal, the patient's serum was also adsorbed on Protein A-Sepharose CL-4B (Pharmacia, Milan, Italy). One milliliter of serum was added to 300 mg of not preswollen resin to avoid dilution of serum. After incubation for 3 hours at room temperature and centrifugation, serum was recovered and used in immunoblotting experiments.
Immunoblotting results:
Kao et al. (2004) [1102] report that 5 proteins bound IgE from the sera of 4 patients with similar masses of approximately 56 kDa. The spot at highest pI, 8.5, was excised and N-terminal amino acid sequencing gave the sequence KMTWTMKAAEEAEAVAN, which is identical to the N-terminal sequence of the mature form of garlic alliin lyase. The other spots with pI between 8.5 and 7 showed closely related sequences from MALDI mass spectroscopy.
The apparent molecular weights of the IgE-binding components identified by all 15 sera ranged from 31 to 60 kDa. The 56 kDa component was detected by all 15 sera. Other IgE-binding components of various molecular weights were detected at frequencies of less than 30%, for example, serum samples 3, 6, 10, and 13 gave a positive reactions to a 42-kDa component.
Pires et al. (2002) [1103] found two IgE binding bands with molecular masses of approximately 12 kDa and around 40-50 kDa, which they suggest probably correspond to the mannose-binding lectin and alliinase.
Perez-Pimiento et al. (1999) [1108] report that IgE from the patient's serum bound to a band at a molecular mass of approximately 12 kDa from raw young garlic (stem and bulb), garlic, onion, and leek. Other 12 kDa bands could also be observed with extracts of mugwort pollen and hazelnut. The serum also recognized an intense IgE binding band of about 22 kDa in mugwort pollen.
Asero et al. (1998) [1109] reported that there was weak binding of IgE to a garlic protein at 10 kDa. Adsorption of the patient's serum on protein A to remove IgG antibodies resulted in an intensification of the 10 kDa band and the appearance of further signals at about 20 and 40 kDa (and a possible band near 100 kDa).

Oral provocation

Number of Studies:1-5
Food used and oral provocation vehicle:Not described
Blind:Not described
Number of Patients:Pires et al. (2002) [1103] challenged one 16-month-old boy.
Dose response:Not described.
Symptoms:Pires et al. (2002) [1103] reported that oral challenge with raw garlic was positive with generalized urticaria within 10 min after ingestion. Oral challenge with cooked garlic was negative.

IgE cross-reactivity and Polysensitisation

The Liliaceae family is divided into two subfamilies: Aliolideas (garlic, onion, chives, and leek) and Asparagoidea (asparagus). Sanchez-Hernandez et al. 2000 [1107] report IgE cross-reactivity between asparagus and onion. However, the patient of Perez-Pimiento et al. (1999) [1108] only reacted to young garlic and tolerated garlic cloves, onion, asparagus, and leek several times. The patient of Pires et al. (2002) [1103] had ingested cooked garlic with tolerance from the age of 12 months and had ingested onion from the age of 6 months with no symptoms.

Asero et al. (1998) [1109] report that occasional weak positive reactions are found on SPTs with commercial garlic extract in birch pollen–hypersensitive patients but that these patients can tolerate garlic. The immunoblotting data of Perez-Pimiento et al. (1999) [1108] suggests possible IgE cross-reactivity between garlic and mugwort pollen.

Other Clinical information

Moneret-Vautrin et al. (2002) [1106] in a survey of 589 cases note that sensitization to Liliaceae (garlic, onion and chive) is observed in 4.6% of prick-tests in children and 7.7% of prick-tests in adults.

The effects of cooking garlic seem to either reduce the allergenic potency (Perez-Pimiento et al. 1999) [1108] or to eliminate it (Pires et al. 2002) [1103].

Garlic is a well-recognized cause of allergic contact dermatitis (Delaney et al, 1996 [774]; Sinha et al, 1977 [766]; Burgess, 1952 [1177]), but may also produce an irritant rash, as well as urticaria or a protein contact dermatitis (Jappe et al. 1999 [1104]). Patch testing using neat garlic, or other spices, is known to give rise to false-positive irritant reactions (Kanerva et al. 1996 [1105]). Diallyl disulfide is believed to cause this reaction. Pires et al. (2002) [1103] report that contact challenge was positive (urticaria) with raw garlic and negative with cooked garlic in a 16-month-old boy.

Garlic can also be an occupational aeroallergen (Lybarger et al. 1982 [1178]; Bassioukas et al. 2004 [1179]).

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References (15)

Kao SH, Hsu CH, Su SN, Hor WT, Chang T WH, Chow LP.
Identification and immunologic characterization of an allergen, alliin lyase, from garlic (Allium sativum).
J Allergy Clin Immunol. 113(1):161-168.. 2004
PUBMEDID: 14713923
Pires G, Pargana E, Loureiro V, Almeida MM, Pinto JR.
Allergy to garlic.
Allergy. 2002 Oct;57(10):957-8.. 2002
PUBMEDID: 12269947
Jappe U, Bonnekoh B, Hausen BM, Gollnick H.
Garlic-related dermatoses: case report and review of the literature.
Am J Contact Dermat. 10(1):37-39. . 1999
PUBMEDID: 10072338
Kanerva L, Estlander T, Jolanki R.
Occupational allergic contact dermatitis from spices.
Contact Dermatitis 35(3):157-162.. 1996
PUBMEDID: 8930476
Moneret-Vautrin DA, Morisset M, Lemerdy P, Croizier A, Kanny G.
Food allergy and IgE sensitization caused by spices: CICBAA data (based on 589 cases of food allergy).
Allerg Immunol (Paris). 34(4):135-40.. 2002
PUBMEDID: 12078423
Asero R, Mistrello G, Roncarolo D, Antoniotti PL, Falagiani P.
A case of garlic allergy.
J Allergy Clin Immunol. 101(3):427-428.. 1998
PUBMEDID: 9525465
Perez-Pimiento AJ, Moneo I, Santaolalla M, de Paz S, Fernandez-Parra B, Dominguez-Lazaro AR.
Anaphylactic reaction to young garlic.
Allergy 54(6):626-629.. 1999
PUBMEDID: 10435479
Sanchez-Hernandez MC, Hernandez M, Delgado J, Guardia P, Monteseirin J, Bartolome B, Palacios R, Martinez J, Conde J.
Allergenic cross-reactivity in the Liliaceae family.
Allergy 55(3):297-299.. 2000
PUBMEDID: 10753025
Rabinkov A, Zhu XZ, Grafi G, Galili G, Mirelman D.
Alliin lyase (Alliinase) from garlic (Allium sativum). Biochemical characterization and cDNA cloning.
Appl Biochem Biotechnol. 48(3):149-171. . 1994
PUBMEDID: 7979352
Pastorello EA, Stocchi L, Pravettoni V, Bigi A, Schilke ML, Incorvaia C, Zanussi C.
Role of the elimination diet in adults with food allergy.
J Allergy Clin Immunol. 84(4 Pt 1):475-483.. 1989
PUBMEDID: 2794292
Delaney TA, Donnelly AM.
Garlic dermatitis.
Australas J Dermatol. 37(2):109-110.. 1996
PUBMEDID: 8687326
Sinha SM, Pasricha JS, Sharma R, Kandhari KC.
Vegetables responsible for contact dermatitis of the hands.
Arch Dermatol. 113(6):776-779.. 1977
PUBMEDID: 869548
Burgess JF.
Occupational dermatitis due to onion and garlic.
Can Med Assoc J. 66(3):275.. 1952
PUBMEDID: 14905389
Lybarger JA, Gallagher JS, Pulver DW, Litwin A, Brooks S, Bernstein IL.
Occupational asthma induced by inhalation and ingestion of garlic.
J Allergy Clin Immunol. 69(5):448-454.. 1982
PUBMEDID: 7076985
Bassioukas K, Orton D, Cerio R.
Occupational airborne allergic contact dermatitis from garlic with concurrent Type I allergy.
Contact Dermatitis. 50(1):39-41. . 2004
PUBMEDID: 15059102

Biochemical Information for Alliin lyase

Allergen Name:Alliin lyase
Alternatve Allergen Names:Alliinase
Allergen Designation:None
Protein Family:PFAM PF04864; Alliinase_C
PF04863; EGF_alliinase
Sequence Known?:Yes
Allergen accession No.s:http://us.expasy.org/cgi-bin/niceprot.pl?Q01594
http://us.expasy.org/cgi-bin/niceprot.pl?Q41233
3D Structure Accession No.:http://www.rcsb.org/pdb/cgi/explore.cgi?pdbId=1LK9
Calculated Masses:51451.59 (mature, residues 39-486 without polysaccharide or pyridoxal phosphate)
Experimental Masses:56 kDa
Oligomeric Masses:
Dimer
Allergen epitopes:Not known
Allergen stability:
Process, chemical, enzymatic:Kao et al. (2004) [1102] report that alliin lyase binds lectins and is thus almost certainly a glycoprotein.
Nature of main cross-reacting proteins:
Not known
Allergen properties & biological function:Alliin lyase or alliinase (EC 4.4.1.4) catalyses the production of allicin (thio-2-propene-1-sulfinic acid S-allyl ester), a biologically active compound which is also responsible for the characteristic smell of garlic. Allicin may be an anti-microbial defence compound.
Allergen purification:
Kao et al. (2004) [1102] purified alliin lyase from garlic, leek, shallot, and onion by two chromatographic steps on HiTrap Q-Sepharose and Sephacryl S-100.
Rabinkov et al. 1994 [1129] purified alliin lyase from 60 g. of garlic cloves homogenised in sodium phosphate (90 mls, 20 mM, pH 7.2) containing 10% v/v glycerol, PMSF (1 mM) and pyridoxal phosphate (0.02 mM) (buffer A). The homogenate was filtered twice through cheese cloth and the filtrate centrifuged at 20000 x g for 30 minutes. Polyethylene glycol 8000 was added to 25% (w/v) and the mixture stirred for 20 minutes. The slurry was centrifuged at 20000 x g for 15 minutes. The pellet was resuspended in 120 mls of buffer A and centrifuged at 20000 x g for 20 minutes. The supernatant was loaded onto a hydroxylapatite column (2.2 x 50 cm, DNA-grage bio-gel HTP, Bio-Rad), washed with 50 mM sodium phosphate buffer (pH7.2) and eluted with 0.3M sodium phosphate buffer (pH7.2). The eluate was brought to 50% saturation with sodium sulphate, stirred for 30 minutes and centrifuged at 20000 x g for 15 minutes. The pellet was redissolved in 2mls of 0.1M potassium phosphate (pH7.2), diluted with the same volume of sodium sulphate (2M) and loaded onto an HPLC hydrophobic interaction column (7.5 x 75 mm, Ultrapac TSK Phenyl 5PW, LKB). Fractions were eluted with a gradient of 1.0-0.0M sodium sulphate in 0.1M potassium phosphate (pH7.2) and alliin lyase activity identified. All steps were at 4°C.
Other biochemical information:
The involvement of carbohydrate groups in the antigenic and allergenic determinants of garlic alliin lyase was suggested by a reduction in IgE binding in immunoblots after periodate oxidation of PVDF membranes bearing the purified garlic protein (Kao et al. 2004) [1102].
The DNA sequence was initially determined by Van Damme et al. (1992) [926].

References (3)

Kao SH, Hsu CH, Su SN, Hor WT, Chang T WH, Chow LP.
Identification and immunologic characterization of an allergen, alliin lyase, from garlic (Allium sativum).
J Allergy Clin Immunol. 113(1):161-168.. 2004
PUBMEDID: 14713923
Rabinkov A, Zhu XZ, Grafi G, Galili G, Mirelman D.
Alliin lyase (Alliinase) from garlic (Allium sativum). Biochemical characterization and cDNA cloning.
Appl Biochem Biotechnol. 48(3):149-171. . 1994
PUBMEDID: 7979352
Van Damme EJ, Smeets K, Torrekens S, Van Leuven F, Peumans WJ.
Isolation and characterization of alliinase cDNA clones from garlic (Allium sativum L.) and related species.
Eur J Biochem. 209(2):751-757.. 1992
PUBMEDID: 1385120