Deoxycytidine transport in the presence of a cytidine deaminase inhibitor and the transport of uracil in Escherichia coli B.

Dippe, Patricia J. Von; Leung, Kiu; Roy-Burman, S.; Visser, Donald W.

doi:10.1016/s0021-9258(19)41449-x

Cited by 11 publications

(1 citation statement)

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“…In Escherichia coli, cytidine deaminase plays an important role in the transport and utilization of pyrimidine nucleosides (Von Dippe et al, 1975;Hochstadt, 1979;Vita et al, 1983). The enzyme has a molecular weight, estimated by gel filtration, of 56 000.…”

Section: Discussionmentioning

confidence: 99%

Cytidine deaminase from Escherichia coli B. Purification and enzymic and molecular properties

Vita¹,

Amici²,

Cacciamani³

et al. 1985

Biochemistry

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Cytidine deaminase (cytidine aminohydrolase, EC 3.5.4.5) from Escherichia coli has been purified to homogeneity through a rapid and efficient two-step procedure consisting of anion-exchange chromatography followed by preparative electrophoresis. The final preparation is homogeneous, as judged by a single band obtained by disc gel electrophoresis performed in the absence and presence of denaturing agents. The native protein molecular weight determined by gel filtration is 56 000. Sodium dodecyl sulfate disc gel electrophoresis experiments conducted upon previous incubation of the enzyme with dimethyl suberimidate suggest an oligomeric structure of two identical subunits of 33 000 molecular weight. The absorption spectrum of the protein reveals a maximum at 277 nm and a minimum at 255 nm. The isoelectric point is at pH 4.35. Amino acid analysis indicates an excess of acidic amino acid residues as well as six half-cystine residues. No interchain disulfide groups have been evidenced. According to Cleland's nomenclature, kinetic analysis shows a rapid-equilibrium random Uni-Bi mechanism. Cytidine deaminase is competitively inhibited by various nucleosides. Km values for cytidine, deoxycytidine, and 5-methylcytidine are 1.8 X 10(-4), 0.9 X 10(-4), and 12.5 X 10(-4) M, respectively.

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Section: Discussionmentioning

confidence: 99%