title: Molecular cloning, expression and characterization of ribokinase of Leishmania major.
abstract: 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.
authors.affiliation: Department of Medical Biochemistry, University of Nigeria, Enugu 1000004, Nigeria. Ogbunudejim@yahoo.co.uk
authors.forename: Patrick O J
authors.initials: PO
authors.lastname: Ogbunude
authors.forename: Nadia
authors.initials: N
authors.lastname: Lamour
authors.forename: Michael P
authors.initials: MP
authors.lastname: Barrett
mesh_terms: 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
chemical_list: D029968:Escherichia coli Proteins; D011994:Recombinant Proteins; D012266:Ribose; D010770:Phosphotransferases; D017853:Phosphotransferases (Alcohol Group Acceptor); C022534:ribokinase