Enzyme studies on human and snail beta-mannosidase using a fluorescence assay and an HPLC/diode array method with Man beta (1-4)GlcNAc as substrate.
1. Snail beta-mannosidase showed a Km value of 0.05 mM toward MU-beta-Man and could not be inhibited by Man, GlcNAc, Man beta(1-4)GlcNAc, Man beta(1-4)GlcNAc beta(1-N)urea or Man beta(1-4) GlcNAc beta(1-4)GlcNAc. 2. The Km value of the snail enzyme towards Man beta(1-4)GlcNAc, as measured by HPLC, was 10 mM, explaining the lack of inhibition. 3. The Km value of the human serum beta-mannosidase towards MU-beta-Man was 0.3 mM, but the human enzyme was not capable of degrading Man beta(1-4)GlcNAc in detectable amounts.
van Pelt
J
J
University Children's Hospital, Het Wilhelmina Kinderziekenhuis, Utrecht, The Netherlands.
Hokke
C H
CH
Dorland
L
L
Duran
M
M
D000818:Animals; D002240:Carbohydrate Sequence; D002851:Chromatography, High Pressure Liquid; D004187:Disaccharides / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006923:Hymecromone / Q000031:analogs & derivatives / Q000378:metabolism; D007700:Kinetics; D008361:Mannosidases / Q000378:metabolism*; D008969:Molecular Sequence Data; D012908:Snails; D013045:Species Specificity; D013379:Substrate Specificity; D044902:beta-Mannosidase
D004187:Disaccharides; C008512:methylumbelliferyl-alpha-D-mannopyranoside; D006923:Hymecromone; C035093:4-O-mannopyranosyl-2-acetamido-2-deoxyglucose; D008361:Mannosidases; D044902:beta-Mannosidase