Glycosidase activity in the post-ecdysial cuticle of the blue crab, Callinectes sapidus.
We have previously demonstrated a marked change in sugar moieties of glycoproteins of the cuticle of the blue crab, Callinectes sapidus, between 0.5 and 3 h post-ecdysis. The present study has identified a glycosidase that appears in the cuticle during the early post-ecdysial hours. The enzyme has affinities for p-nitrophenyl derivatives of both N-acetylglucosamine and N-acetylgalactosamine. Both activities are competitively inhibited by chitobiose, suggesting that the enzyme could be a N-acetylhexosaminidase (EC 3.2.1.52). Atypical of N-acetylhexosaminidases described to date, this enzyme has a pH optimum of 7.0. The enzyme activity is high during the post-ecdysial period coincident with the changes in glycoprotein profiles observed in vivo. Partial purification of the enzyme has been accomplished by Sephacryl size-exclusion chromatography followed by concanavalin A affinity chromatography.
Roer
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RD
Department of Biological Sciences, University of North Carolina at Wilmington, 601 South College Road, Wilmington, NC 28403-3297, USA. roer@uncwil.edu
Halbrook
K E
KE
Shafer
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TH
D000116:Acetylgalactosamine / Q000031:analogs & derivatives* / Q000378:metabolism; D000818:Animals; D003386:Brachyura / Q000201:enzymology* / Q000502:physiology; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D018978:Molting; D013379:Substrate Specificity
C014123:4-nitrophenyl-2-acetamido-2-deoxygalactopyranoside; D006026:Glycoside Hydrolases; D000116:Acetylgalactosamine