title: Plasma methylumbelliferyl-tetra-N-acetyl-chitotetraoside hydrolase: further study of its characteristics as a chitinase and comparison with its activity on Remazol Brilliant Violet carboxymethyl chitin.
abstract: We have further studied some characteristics of human plasma specific chitinase by making use of the fluorescent substrate methylumbelliferyl-tetra-N-acetyl-beta-D-chitotetraoside (MU-TACT). The enzyme is also active towards the substrates MU-di-N-acetyl-beta-D-chitobioside (MU-DACB) and MU-N-acetyl-chitotrioside (MU-TRACT). MU-TACT hydrolase in plasma is very stable. It is inhibited by the substrate and the product of the reaction and by allosamidin and ethyleneglycolchitin. When the activity of plasma MU-TACT hydrolase was compared to Remazol Brilliant Violet carboxymethyl (RBV) chitin hydrolase (RBV chitinase), it appeared that another enzyme--lysozyme--is also active on RBV chitin and this enzyme represents about 50-60% of the total RBV chitinase activity. Highly increased activity of plasma MU-TACT hydrolase in plasma of Gaucher patients was reflected in a similar increase of RBV chitin hydrolase. In these patients, both MU-TACT hydrolase and RBV chitinase are totally inhibited by allosamidin indicating that specific chitinase is the increased enzyme. With the MU-TACT substrate, specific chitinase is measured and with RBV chitin as substrate the measured activity is a combination of specific chitinase (activity inhibited by allosamidin) as well as lysozyme (residual activity after allosamidin inhibition). For measurement of specific chitinase in human plasma and clinical applications, the di-, tri- or tetra-N-acetylglucosamine derivatives of MU are recommended. In order to avoid confusion, recommended names are either the total substrate followed by -ase, or chitinase.
authors.affiliation: Faculty of Medicine, University of Antwerp, Wilrijk, Belgium.
authors.forename: W R
authors.initials: WR
authors.lastname: Den Tandt
authors.forename: S
authors.initials: S
authors.lastname: Scharpé
mesh_terms: D000208:Acute Disease; D002240:Carbohydrate Sequence; D002686:Chitin / Q000031:analogs & derivatives* / Q000378:metabolism; D002688:Chitinases / Q000097:blood*; D005776:Gaucher Disease / Q000097:blood / Q000201:enzymology; D006596:Hexosaminidases / Q000037:antagonists & inhibitors / Q000097:blood*; D006801:Humans; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000097:blood / Q000201:enzymology; D007951:Leukemia, Myeloid / Q000097:blood / Q000201:enzymology; D008969:Molecular Sequence Data; D009081:Mucolipidoses / Q000097:blood / Q000201:enzymology; D009282:Naphthalenesulfonates
chemical_list: D009282:Naphthalenesulfonates; C111247:C.I. Reactive Violet 5; D002686:Chitin; C057702:4-methylumbelliferyl-tetra-N-acetyl-beta-D-chitotetraoside hydrolase; D006596:Hexosaminidases; D002688:Chitinases