Biomaterial Database

Camel lens zeta-crystallin kinetics and its inhibition by dicoumarol. 1996

A S Duhaiman

Department of Biochemistry, King Saud University, Riyadh, Saudi Arabia.

zeta-Crystallin a novel NADPH quinone oxidoreductase of the camel lens is capable of reducing a non quinone compound such as 2,6-dichlorophenolindophenol (DCIP) which is mediated by NADPH. A classical Michaelis-Menten kinetics were exhibited for both DCIP and NADPH with Km values of 15.3 microM and 7.0 microM respectively, at pH 7.8. The Vmax was 1.60 mumol./min.mg protein. The results of steady-state kinetic analysis indicated that the reaction proceeds through a Ping-Pong mechanism. Dicoumarol was found to be a competitive inhibitor of zeta-crystallin with respect to DCIP with a Ki value of 14.6 microM and showed uncompetitive inhibition with respect to NADPH with a Ki value of 36.2 microM.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D009249	NADP	Nicotinamide adenine dinucleotide phosphate. A coenzyme composed of ribosylnicotinamide 5'-phosphate (NMN) coupled by pyrophosphate linkage to the 5'-phosphate adenosine 2',5'-bisphosphate. It serves as an electron carrier in a number of reactions, being alternately oxidized (NADP+) and reduced (NADPH). (Dorland, 27th ed)	Coenzyme II,Nicotinamide-Adenine Dinucleotide Phosphate,Triphosphopyridine Nucleotide,NADPH,Dinucleotide Phosphate, Nicotinamide-Adenine,Nicotinamide Adenine Dinucleotide Phosphate,Nucleotide, Triphosphopyridine,Phosphate, Nicotinamide-Adenine Dinucleotide
D001728	Dicumarol	An oral anticoagulant that interferes with the metabolism of vitamin K. It is also used in biochemical experiments as an inhibitor of reductases.	Bishydroxycoumarin,Dicoumarin,Dicoumarol
D002162	Camelus	Two-toed, hoofed mammals with four legs, a big-lipped snout, and a humped back belonging to the family Camelidae. They are native to North Africa, and Western and Central Asia.	Camels,Dromedary,Bactrian Camels,Bractrian Camels,Camelus bactrianus,Camelus dromedarius,Bactrian Camel,Bractrian Camel,Camel,Camel, Bactrian,Camel, Bractrian,Camels, Bactrian,Camels, Bractrian,Dromedaries
D003459	Crystallins	A heterogeneous family of water-soluble structural proteins found in cells of the vertebrate lens. The presence of these proteins accounts for the transparency of the lens. The family is composed of four major groups, alpha, beta, gamma, and delta, and several minor groups, which are classed on the basis of size, charge, immunological properties, and vertebrate source. Alpha, beta, and delta crystallins occur in avian and reptilian lenses, while alpha, beta, and gamma crystallins occur in all other lenses.	Lens Proteins,Crystallin,Eye Lens Protein,Lens Protein, Eye,Protein, Eye Lens,Proteins, Lens
D004791	Enzyme Inhibitors	Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.	Enzyme Inhibitor,Inhibitor, Enzyme,Inhibitors, Enzyme
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D015086	2,6-Dichloroindophenol	A dye used as a reagent in the determination of vitamin C.	2,6-Dichlorophenolindophenol,Sodium 2,6-Dichloroindophenol,Tillmans' Reagent,2,6 Dichloroindophenol,2,6-Dichlorobenzenoneindophenol Dye,Dichlorophenol Indophenol,Dichlorophenolindophenol,Tillmans Reagent,2,6 Dichlorobenzenoneindophenol Dye,2,6 Dichlorophenolindophenol,2,6-Dichloroindophenol, Sodium,Dichloroindophenol, 2,6,Dye, 2,6-Dichlorobenzenoneindophenol,Indophenol, Dichlorophenol,Reagent, Tillmans,Reagent, Tillmans',Sodium 2,6 Dichloroindophenol,Tillman Reagent,Tillman's Reagent