Identification of physicochemical properties of Scylla paramamosain allergen, arginin kinase.
BACKGROUND
Arginine kinase (AK) is expressed in a wide variety of species, including human food sources (seafood) and pests (cockroaches and moths), and has been reported as a novel allergen. However, there has been little research on the allergenicity of AK in crustaceans. In this study the physicochemical properties of AK from mud crab (Scylla paramamosain) were investigated.


RESULTS
Analysis by sodium dodecyl sulfate polyacrylamide gel electrophoresis, immunoblotting and inhibition enzyme-linked immunosorbent assay revealed that purified AK was unstable in thermal processing and in acid buffer. Under simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) conditions, purified AK was much more readily degraded by pepsin than by trypsin or chymotrypsin. The unpurified AK in crab myogen degraded more markedly than purified AK. In addition, in two-phase gastrointestinal digestion, AK was rapidly degraded by pepsin but resistant to trypsin and chymotrypsin digestion, while tropomyosin derived from mud crab was resistant to pepsin digestion but digested readily by trypsin or chymotrypsin. Further study of serum samples obtained from crab-allergic human patients indicated that the allergenicity of AK was markedly reduced by digestion with SGF but not SIF.


CONCLUSIONS
AK is an important food allergen despite its unstable physicochemical properties of digestibility.
College of Biological Engineering, The Key Laboratory of Science and Technology for Aquaculture and Food Safety, Jimei University, 43 Yindou Road, Xiamen 361021, Fujian, China.
Hui-Lin
HL
Yu
Wei-Wei
WW
Ruan
Min-Jie
MJ
Cao
Qiu-Feng
QF
Cai
Hai-Wang
HW
Shen
Guang-Ming
GM
Liu
D000485:Allergens / Q000009:adverse effects / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D000818:Animals; D001122:Arginine Kinase / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D060829:Arthropod Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D003386:Brachyura / Q000737:chemistry* / Q000201:enzymology / Q000254:growth & development; D055598:Chemical Phenomena; D002681:China; D004044:Dietary Proteins / Q000032:analysis / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism; D004063:Digestion; D004795:Enzyme Stability; D005512:Food Hypersensitivity / Q000097:blood / Q000276:immunology; D005750:Gastric Juice / Q000201:enzymology / Q000378:metabolism; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007073:Immunoglobulin E / Q000378:metabolism; D055595:Mechanical Phenomena; D008958:Models, Molecular; D010434:Pepsin A / Q000378:metabolism; D017434:Protein Structure, Tertiary; D059748:Proteolysis; D012758:Shellfish / Q000009:adverse effects / Q000032:analysis*
D000485:Allergens; D060829:Arthropod Proteins; D004044:Dietary Proteins; D007073:Immunoglobulin E; D001122:Arginine Kinase; D010434:Pepsin A