Analysis of hydrolytic activity of a 65-kDa chitinase from the silkworm, Bombyx mori.
The hydrolytic reactions of Bombyx mori 65-kDa chitinase with the short substrates, N-acetyl-chitooligosaccharides, were analyzed by HPLC. Analysis of the hydrolyzed products showed that the newly produced oligosaccharides are all beta anomers, suggesting that, similar to other family 18 glycosyl hydrolases, the 65-kDa chitinase acts in the retaining mechanism. Furthermore, the enzyme cleaves the N-acetylchitooligosaccharides mainly at the linkage between the second and the third GlcNAc moieties from the non-reducing end, while the other sites were cleaved in smaller proportions. Moreover, the initial reaction rates of the enzyme with the longer N-acetylchitooligosaccharides were higher than those with shorter ones. These results suggest that the enzyme is an endo-cleaving type and more efficient on the longer substrates.
Abdel-Banat
Babiker M A
BM
Department of Biological Science, Faculty of Agriculture, Yamaguchi University, Japan.
Zhou
Weiwen
W
Karasuda
Shuji
S
Koga
Daizo
D
D000818:Animals; D012831:Bombyx / Q000201:enzymology*; D002688:Chitinases / Q000737:chemistry / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D006868:Hydrolysis
D002688:Chitinases