Characterization of a high activity form of ribonucleoside diphosphate reductase from Escherichia coli.
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چکیده
منابع مشابه
Physicochemical characterization of ribonucleoside diphosphate reductase from Escherichia coli.
Ribonucleotide reductase from Escherichia coli consists of two nonidentical subunits, proteins Bl and B2. Affinity chromatography resulted in a Bl preparation which appeared homogeneous during polyacrylamide gel electrophoresis and ultracentrifugation. The molecular weight was 160,000 by sedimentation equilibrium centrifugation using a partial specific volume of 0.706 ml per g at 4”. Protein Bl...
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Ribonucleoside diphosphate reductase consists of two nonidentical subunits, proteins Bl and B2. The enzyme catalyzes the reduction of ribonucleotides to the corresponding deoxyribonucleotides. The electrons required in this reduction are transported from NADPH via a flavoprotein, thioredoxin reductase, to a low molecular weight protein, thioredoxin. The reduced form of thioredoxin acts as hydro...
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Ribonucleoside diphosphate reductase is an allosteric enzyme consisting of two nonidentical subunits, proteins Bl and B2. Bl contains dithiols which participate in the oxidation-reduction reactions of electron transport, while B2 contains a free radical essential for activity. Ribonucleoside diphosphates are bound to Bl but not to B2. Addition of 2’-deoxy-2’-chloro ribonucleoside diphosphates t...
متن کاملMechanism of ribonucleoside diphosphate reductase from Escherichia coli. Evidence for 3'-C--H bond cleavage.
Incubation of the pyrimidine [3'-3H]UDP with ribonucleotide reductase resulted in an isotope effect on the conversion to dUDP which varied as a function of pH and allosteric effectors (pH, kH/kT, effector): 6.6, 4.7, ATP; 7.6, 3.3, ATP; 7.6, 2.6, dATP; 7.6, 2.0, TTP; 8.4, 2.8, ATP. During this reaction 3H2O was also released. The lower the pH of the reaction, the larger the isotope effect, and ...
متن کاملActive site of ribonucleoside diphosphate reductase from Escherichia coli. Inactivation of the enzyme by 2'-substituted ribonucleoside diphosphates.
Ribonucleoside diphosphate reductase is an allosteric enzyme consisting of two nonidentical subunits, proteins B1 and B2. B1 contains dithiols which participate in the oxidation-reduction reactions of electron transport, while B2 contains a free radical essential for activity. Ribonucleoside diphosphates are bound to B1 but not to B2. Addition of 2'-deoxy-2'-chloro ribonucleoside diphosphates t...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1979
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(18)50553-6