tailieunhanh - The effect of organic compounds on the chitinase activity the dissociation constant calculation of the "Chitinase-metallic ion" complex

The effect of some organic compounds on the activity of chitinase from Serratia marcescens has been investigated. Among these compounds, 1,10-phenanthroline was found to be an inhibitor and ethanol - an activator of the chitinase activity; - ’ dipyridyl and Zn2+ do not take any effect on the chitinase activity. In this investigation, the dissociation constant of an chitinase-metalic ion complex (K1) and the inhibition constant (K2) have been estimated with K1 = mcM and K2 = mM. | Journal of Chemistry Vol. 41 No. 2 P. 110 -114 2003 THE EFFECT OF ORGANIC COMPOUNDS ON THE CHITINASE ACTIVITy THE DISSOCIATION CONSTANT CALCULATION OF THE CHITINASE-METALLIC ION COMPLEX Received 12-3-2002 NAQyQKI TANIGUCHI 1 YQSHITAKA IKEDA1 TRAN DINH TQAI2 department of Biochemistry Osaka University Medical School Japan institute of Chemistry National Center for Natural Science and Technology of Vietnam SUMMARy The effect of some organic compounds on the activity of chitinase from Serratia marcescens has been investigated. Among these compounds 1 10-phenanthroline was found to be an inhibitor and ethanol - an activator of the chitinase activity a-a dipyridyl and Zn2 do not take any effect on the chitinase activity. In this investigation the dissociation constant of an chitinase-metalic ion complex K1 and the inhibition constant K2 have been estimated with K1 mcM and K2 mM. I - INTRODUCTION Chitinases EC belong to numbers of glycosyl hydrolases. These numbers related enzymes 482 sequences corresponding to 52 EC entries of the classification system have been classified into 45 families. Chitinases catalyze the hydrolysis of chitin an insoluble linear P 1 4 -linked polymer of N-acetyl-glucosamine GlcNAc and are critical for the normal development of insects. On the basis of amino acid sequence five known classes of Chitinases are grouped into two glycosyl hydrolase families 1 2 . Family 18 consists of class III and class V Chitinases found in a wide range of organisms including bacteria plants animals fungi and viruses. Family 19 consists of class I II and IV Chitinases and is found only in plants. The enzyme structures and hydrolysis mechanisms for two families appear to be quite different. The knowledge of the reaction mechanism is important for the design of understanding properties of this enzyme 3 4 . A typical colorimetric substrate for assaying exochitinase activity is p-nitrophenyl -N-acetyl-beta-D-glucosaminide pNP-beta-GlucNAc and .