Enzymes of Purine Metabolism in Mycoplasma mycoides subsp. mycoides
AUTOR(ES)
Mitchell, Alana
RESUMO
The major pathways of ribonucleotide biosynthesis in Mycoplasma mycoides subsp. mycoides were proposed previously from studies of its usage of radioactive purines and pyrimidines. To interpret more fully the pattern of purine usage, we have assayed cell-free extracts of this organism for several enzymes associated with the salvage synthesis of purine nucleotides. M. mycoides possessed phosphoribosyltransferases for adenine, guanine, and hypoxanthine, purine nucleoside phosphorylase, GMP reductase, GMP kinase, adenylosuccinate synthetase, and adenylosuccinate lyase. Purine nucleoside kinase and adenosine deaminase were not detected. Examination of kinetic properties and regulation of some of the above enzymes revealed differences between M. mycoides and Escherichia coli. Most notable of these were the greater susceptibility of the enzymes from M. mycoides to inhibition by nucleotides and the more widespread involvement of GMP as an inhibitor. Observations on enzyme activities in vitro allow an adequate explanation of the capacity of guanine to provide M. mycoides with its full requirement for purine nucleotides.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=222314Documentos Relacionados
- Enzymes of Pyrimidine Metabolism in Mycoplasma mycoides subsp. mycoides
- Enzymes of pyrimidine deoxyribonucleotide metabolism in Mycoplasma mycoides subsp. mycoides.
- Genetic and Serological Analysis of Lipoprotein LppA in Mycoplasma mycoides subsp. mycoides LC and Mycoplasma mycoides subsp. capri
- Pathways of Nucleotide Biosynthesis in Mycoplasma mycoides subsp. mycoides
- Pathways of pyrimidine deoxyribonucleotide biosynthesis in Mycoplasma mycoides subsp. mycoides.