Avtor/Urednik		Stojan, Jure; Goličnik, Marko; Fournier, Didier
Naslov		Rational polynomial equation as an unbiased approach for the kinetic studies of Drosophila melanogaster acetylcholinesterase reaction mechanism
Tip		članek
Vir		Biochim Biophys Acta - Proteins and proteomics
Vol. in št.		Letnik 1703
Leto izdaje		2004
Obseg		str. 53-61
Jezik		eng
Abstrakt		The hydrolysis of substratcs by cholinesterases does not follow the Michaelis-Menten reaction mechanism. The well-known inhibition by excess substrate is often accompanied by an unexpectedly high activity at low substrate concentrations. It appears that these peculiarities are the consequence of an unusual architeclure of the active site, which conducts the substrate molecule over many stages before it is cleaved and released. Structural and kinetic data also suggest thal two substrate molecules can attach at the same time to the free, as well as to the acetylated, enzyme. We present a procedure which provides an unbiased framework for mathematical modelling of such complex reaction mechanisms. It is based on regression analysis of a rational polynomial using classical initial rate data. The deterrnination of polynomial degree reveals the number of independent parameters that can be evaluated from the available information. Once determined, these parameters can substantially facilitate the construction and evaluation of a kinetic model reflecting the expected molecular events in an enzymic reaetion. We also present practical suggestions for testing the postulated kinetic model, using an original thermodynamic approach and an isolated effect in a specifically mutated enzyme.
Deskriptorji		DROSOPHILA MELANOGASTER ACETYLCHOLINESTERASE KINETICS BINDING SITES ACETYLTHIOCHOLINE MODELS, THEORETICAL LEAST-SQUARES ANALYSIS