Biomaterial Database

[Role of the carboxylic groups in interaction of phenylalanyl-tRNA synthetase with substrates]. 1981

I I Gorshkova, and O I Lavrik, and V V Filippov

The effect of modification of carboxylic groups of phenylalanyl-tRNA synthetase by p-toluene sulfonate N-cyclohexyl-N'-beta-(4-methylmorpholine) ethylcarbodiimide (CMEC) on the activity of the enzyme was investigated. It was shown that modification of two moles of carboxylic groups per mole of the enzymes leads to the diminution of negative charge of the enzyme and to inactivation in ATP-[32P]PPi-exchange and aminoacylation reactions. The inactivation is completely reversed by mild alkaline hydrolysis. ATP in concentration 2 X 10(-4) M partially protects the enzyme against inactivation, protective effect being stimulated by Mg2+ and 0.4-0.7 moles of carboxylic groups per mole of the enzyme are protected against inactivation is observed although the depth of modification is increased. Other substrates do not have protective effect. Modification of the enzyme by CMEC increases Kdiss value of [14C]-Phe-tRNA enzyme complex and Km value for tRNAPhe in aminoacylation by factor of three. Vmax for all substrates in both aminoacylation and leads to 40% increase of Hill's coefficient for ATP in ATP-[32P]PPi-exchange reaction but not in aminoacylation. The carboxylic groups modified by CMEC are assumed to take part in ATP recognition and in catalysis of the ATP conversion and in catalysis of transfer of activated amino acid residues on tRNA.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D010652	Phenylalanine-tRNA Ligase	An enzyme that activates phenylalanine with its specific transfer RNA. EC 6.1.1.20.	Phenylalanyl T RNA Synthetase,Phe-tRNA Ligase,Phenylalanyl-tRNA Synthetase,Ligase, Phe-tRNA,Ligase, Phenylalanine-tRNA,Phe tRNA Ligase,Phenylalanine tRNA Ligase,Phenylalanyl tRNA Synthetase,Synthetase, Phenylalanyl-tRNA
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
D003028	CME-Carbodiimide		4-(2-((Cyclohexylimidocarbonyl)amino)ethyl)-4-methylmorpholinium,CME Carbodiimide,CMEC,Carbodiimide, CME
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
D000255	Adenosine Triphosphate	An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.	ATP,Adenosine Triphosphate, Calcium Salt,Adenosine Triphosphate, Chromium Salt,Adenosine Triphosphate, Magnesium Salt,Adenosine Triphosphate, Manganese Salt,Adenylpyrophosphate,CaATP,CrATP,Manganese Adenosine Triphosphate,MgATP,MnATP,ATP-MgCl2,Adenosine Triphosphate, Chromium Ammonium Salt,Adenosine Triphosphate, Magnesium Chloride,Atriphos,Chromium Adenosine Triphosphate,Cr(H2O)4 ATP,Magnesium Adenosine Triphosphate,Striadyne,ATP MgCl2
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
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D013379	Substrate Specificity	A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.	Specificities, Substrate,Specificity, Substrate,Substrate Specificities