Biomaterial Database

Reverse and forward reactions of carbamyl phosphokinase from Streptococcus faecalis R. Participation of nucleotides and reaction mechanisms. 1981

V N Pandey, and D S Pradhan

The participation of Mg complex of nucleoside diphosphates and nucleoside triphosphates in the reverse and forward reactions catalyzed by purified carbamyl phosphokinase (ATP : carbamate phosphotransferase, EC 2.7.2.2) of Streptococcus faecalis R, ATCC-8043 were studied. The results of initial velocity studies of approx. 1 mM free Mg2+ concentration have indicated that in the reverse reaction MgdADP was as effective a substrate as MgADP. The phosphoryl group transfer from carbamyl phosphate to MgGDP, MgCDP and MgUDP was also observed at relatively higher concentrations of the enzyme and respective magnesium nucleoside diphosphate. In the forward direction MgdATP was found to be as efficient a phosphate donor as MgATP. On the other hand, Mg complexes of GTP, CTP and UTP were ineffective even at higher concentrations of the enzyme and respective magnesium nucleoside triphosphate. Product inhibition studies carried out at non-inhibitory level of approx. 1 mM free Mg2+ concentration have revealed that the enzyme has two distinct sites, one for nucleoside diphosphate or nucleoside triphosphate and the other for carbamyl phosphate or carbamate, and its reaction with the substrates is of the random type. Further tests of numerical values for kinetic constants have indicated that they are partially consistent with the Haldane relationship which is characteristic of rapid equilibrium and random mechanism.

UI	MeSH Term	Description	Entries
D008274	Magnesium	A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
D009711	Nucleotides	The monomeric units from which DNA or RNA polymers are constructed. They consist of a purine or pyrimidine base, a pentose sugar, and a phosphate group. (From King & Stansfield, A Dictionary of Genetics, 4th ed)	Nucleotide
D010770	Phosphotransferases	A rather large group of enzymes comprising not only those transferring phosphate but also diphosphate, nucleotidyl residues, and others. These have also been subdivided according to the acceptor group. (From Enzyme Nomenclature, 1992) EC 2.7.	Kinases,Phosphotransferase,Phosphotransferases, ATP,Transphosphorylase,Transphosphorylases,Kinase,ATP Phosphotransferases
D003565	Cytidine Diphosphate	Cytidine 5'-(trihydrogen diphosphate). A cytosine nucleotide containing two phosphate groups esterified to the sugar moiety. Synonyms: CRPP; cytidine pyrophosphate.	CDP,Diphosphate, Cytidine
D003838	Deoxyadenine Nucleotides	Adenine nucleotides which contain deoxyribose as the sugar moiety.	Deoxyadenosine Phosphates,Nucleotides, Deoxyadenine,Phosphates, Deoxyadenosine
D006153	Guanosine Diphosphate	A guanine nucleotide containing two phosphate groups esterified to the sugar moiety.	GDP,Guanosine 5'-Diphosphate,Guanosine 5'-Trihydrogen Diphosphate,5'-Diphosphate, Guanosine,5'-Trihydrogen Diphosphate, Guanosine,Diphosphate, Guanosine,Diphosphate, Guanosine 5'-Trihydrogen,Guanosine 5' Diphosphate,Guanosine 5' Trihydrogen Diphosphate
D000244	Adenosine Diphosphate	Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position.	ADP,Adenosine Pyrophosphate,Magnesium ADP,MgADP,Adenosine 5'-Pyrophosphate,5'-Pyrophosphate, Adenosine,ADP, Magnesium,Adenosine 5' Pyrophosphate,Diphosphate, Adenosine,Pyrophosphate, Adenosine
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
D013293	Enterococcus faecalis	A species of gram-positive, coccoid bacteria commonly isolated from clinical specimens and the human intestinal tract. Most strains are nonhemolytic.	Streptococcus Group D,Streptococcus faecalis
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