tailieunhanh - Báo cáo khoa học: Common G102S polymorphism in chitotriosidase differentially affects activity towards 4-methylumbelliferyl substrates

Chitotriosidase (CHIT1) is a chitinase that is secreted by activated macro-phages. Plasma chitotriosidase activity reflects the presence of lipid-laden macrophages in patients with Gaucher disease. CHIT1 activity can be con-veniently measured using fluorogenic 4-methylumbelliferyl (4MU)–chitotri-oside or 4MU–chitobioside as the substrate, however, nonsaturating concentrations have to be used because of apparent substrate inhibition. | ễFEBS Journal Common G102S polymorphism in chitotriosidase differentially affects activity towards 4-methylumbelliferyl substrates Anton P. Bussink1 Marri Verhoek1 Jocelyne Vreede2 Karen Ghauharali-van der Vlugt1 Wilma E. Donker-Koopman1 Richard R. Sprenger1 Carla E. Hollak3 Johannes M. F. G. Aerts1 and Rolf G. Boot1 1 Department of MedicalBiochemistry Academic MedicalCenter University of Amsterdam The Netherlands 2 Van t Hoff Institute for Molecular Sciences University of Amsterdam The Netherlands 3 Department of InternalMedicine Academic MedicalCenter University of Amsterdam The Netherlands Keywords chitinase chitotriosidase Gaucher disease molecular dynamics simulation single nucleotide polymorphism Correspondence R. G. Boot Department of Medical Biochemistry Academic MedicalCenter Meibergdreef 15 1105 AZ Amsterdam The Netherlands Fax 31 2069 15519 Tel 31 2056 65157 E-mail Received 20 May 2009 revised 10 July 2009 accepted 5 August 2009 doi Chitotriosidase CHIT1 is a chitinase that is secreted by activated macrophages. Plasma chitotriosidase activity reflects the presence of lipid-laden macrophages in patients with Gaucher disease. CHIT1 activity can be conveniently measured using fluorogenic 4-methylumbelliferyl 4MU -chitotri-oside or 4MU-chitobioside as the substrate however nonsaturating concentrations have to be used because of apparent substrate inhibition. Saturating substrate concentrations can however be used with the newly designed substrate 4MU-deoxychitobioside. We studied the impact of a known polymorphism G102S on the catalytic properties of CHIT1. The G102S allele was found to be common in type I Gaucher disease patients in the Netherlands 24 of alleles . The catalytic efficiency of recombinant Ser102 CHIT1 was 70 that of wild-type Gly102 CHIT1 when measured with 4MU-chitotrioside at a nonsaturating concentration. However the activity was normal with 4MU-deoxychitobioside as the substrate at .