Premium
Cry j 2, a major allergen of Japanese cedar pollen, shows polymethylgalacturonase activity
Author(s) -
Ohtsuki T.,
Taniauchi Y.,
Kohno K.,
Fukuda S.,
Usui M.,
Kurimoto M.
Publication year - 1995
Publication title -
allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.363
H-Index - 173
eISSN - 1398-9995
pISSN - 0105-4538
DOI - 10.1111/j.1398-9995.1995.tb01183.x
Subject(s) - pectinase , chemistry , biochemistry , aspergillus niger , enzyme , pectin , enzyme assay , hydrolysis , cryptomeria , biology , botany , japonica
We examined Cry j 2, a major allergen of Japanese cedar (Cryptomeria japonica) pollen, for polygalacturonase enzyme activity, since a nucleotide sequence of cDNA of Cry j 2 showed a significant homology with that of tomato polygalacturonase. Polygalacturonase is well known to depolymerize preferentially polygalacturonic acid (PGA) by hydrolysis. However, Cry j 2 did not act on PGA, but was found to depolymerize pectin and methylesterified PGA in a dose‐dependent manner. The substrate specificity of Cry j 2 was different from that of polygalacturonase derived from Aspergillus niger. The depolymerizing activity of Cry j 2 reached a maximum at 50%‐60% of methylesterification of PGA. In contrast, polygalacturonase showed its maximum activity to PGA, and the activity decreased as the degree of methylesterification increased. Interestingly, the pectin‐depolymerizing activity of Cry j 2 was due to a hydrolysis, but not a lyase, activity which splits the glycosidic bonds by β‐elimination, since no unsaturated uronides were found by measurement of absorbance at 235 nm in the reaction mixture. The enzyme activity was markedly inhibited by anti‐Cry j 2 antibodies. These results indicate that Cry j 2 probably has polymethylgalacturonase enzyme activity, as postulated by von Neukom in 1963, although existence of this activity has not yet been proven.