Molecular cloning, expression and characterization of ribokinase of Leishmania major.
Ribokinase (EC 2.1.7.15) from Leishmania major was cloned, sequenced and overexpressed in Escherichia coli. The gene expressed an active enzyme that had comparable activity to the same enzyme studied in E. coli. It specifically phosphorylated D-ribose. Under defined conditions, the K(m) for the substrates D-ribose and ATP were 0.3+/-0.04 mM and 0.2+/-0.02 mM, respectively. The turnover numbers of the enzyme for the substrates were 10.8 s(-1) and 10.2 s(-1), respectively. The enzyme product ribose 5-phosphate inhibited the phosphorylation of D-ribose with an apparent K(i) of 0.4 mM, which is close to the K(m) (0.3 mM) of D-ribose, suggesting that it might play a role in regulating flux through the enzyme.
Ogbunude
Patrick O J
PO
Department of Medical Biochemistry, University of Nigeria, Enugu 1000004, Nigeria. Ogbunudejim@yahoo.co.uk
Lamour
Nadia
N
Barrett
Michael P
MP
D000818:Animals; D003001:Cloning, Molecular; D004789:Enzyme Activation; D029968:Escherichia coli Proteins / Q000737:chemistry; D015870:Gene Expression; D007700:Kinetics; D018320:Leishmania major / Q000201:enzymology*; D008970:Molecular Weight; D010770:Phosphotransferases / Q000235:genetics / Q000378:metabolism; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism*; D011994:Recombinant Proteins; D012266:Ribose / Q000378:metabolism*; D013379:Substrate Specificity
D029968:Escherichia coli Proteins; D011994:Recombinant Proteins; D012266:Ribose; D010770:Phosphotransferases; D017853:Phosphotransferases (Alcohol Group Acceptor); C022534:ribokinase