Biomaterial Database

Isoleucyl transfer ribonucleic acid synthetase. Steady-state kinetic analysis. 1979

J G Moe, and D Piszkiewicz

A steady-state kinetic analysis was conducted of the overall aminoacylation reaction catalyzed by isoleucyl-tRNA synthetase. The patterns of Lineweaver-Burk plots obtained indicated that tRNA adds to the enzyme only after isoleucyl adenylate formation and pyrophosphate release. These kinetic patterns were consistent with the bi-uni-uni-bi Ping Pong mechanism generally accepted for this aminoacyl-tRNA synthetase, but they could also be accommodated by a mechanism in which a second molecule of L-isoleucine added to the enzyme between isoleucyl adenylate formation and aminoacylation of tRNA [Fersht, A.R., & Kaethner, M.M. (1976) Biochemistry 15, 818]. The values of the kinetic parameters favor the latter mechanism. The results of this kinetic analysis indicated that the affinity of isoleucyl-tRNA synthetase for Mg.ATP was enhanced upon binding of L-isoleucine and vice versa. It also indicated that the affinity of the enzyme for L-isoleucine is decreased upon binding tRNA and vice versa. The values of dissociation constants calculated for each of the substrates by this study generally compared well with those determined by other authors using a variety of kinetic and equilibrium methods.

UI	MeSH Term	Description	Entries
D007533	Isoleucine-tRNA Ligase	An enzyme that activates isoleucine with its specific transfer RNA. EC 6.1.1.5.	Isoleucyl T RNA Synthetase,Isoleucyl- tRNA Synthetase ILS1,Isoleucyl-tRNA Synthetase 1,Isoleucyl-tRNA Synthetase ILES1,Ile-tRNA Ligase,Isoleucyl-tRNA Synthetase,1, Isoleucyl-tRNA Synthetase,ILES1, Isoleucyl-tRNA Synthetase,Ile tRNA Ligase,Isoleucine tRNA Ligase,Isoleucyl tRNA Synthetase,Isoleucyl tRNA Synthetase 1,Isoleucyl tRNA Synthetase ILES1,Isoleucyl tRNA Synthetase ILS1,Ligase, Ile-tRNA,Ligase, Isoleucine-tRNA,Synthetase 1, Isoleucyl-tRNA,Synthetase ILES1, Isoleucyl-tRNA,Synthetase, Isoleucyl-tRNA
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008433	Mathematics	The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Mathematic
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D000604	Amino Acyl-tRNA Synthetases	A subclass of enzymes that aminoacylate AMINO ACID-SPECIFIC TRANSFER RNA with their corresponding AMINO ACIDS.	Amino Acyl T RNA Synthetases,Amino Acyl-tRNA Ligases,Aminoacyl Transfer RNA Synthetase,Aminoacyl-tRNA Synthetase,Transfer RNA Synthetase,tRNA Synthetase,Acyl-tRNA Ligases, Amino,Acyl-tRNA Synthetases, Amino,Amino Acyl tRNA Ligases,Amino Acyl tRNA Synthetases,Aminoacyl tRNA Synthetase,Ligases, Amino Acyl-tRNA,RNA Synthetase, Transfer,Synthetase, Aminoacyl-tRNA,Synthetase, Transfer RNA,Synthetase, tRNA,Synthetases, Amino Acyl-tRNA