title: Rat liver ribonucleotide reductase: separation, purification, and properties of two nonidentical subunits.
abstract: Two nonidentical subunits of mammalian ribonucleotide reductase, L1 and L2, from regenerating rat liver have been extensively purified for the first time. They were separated by dATP-Sepharose affinity chromatography. Subunit L1, which bound to dATP-Sepharose, was eluted with 50 mM ATP and purified to homogeneity (as demonstrated by sodium dodecyl sulfate (SDS) - polyacrylamide gel electrophoresis) by molecular exclusion high-pressure liquid chromatography (HPLC). This subunit had an apparent relative mass (Mr) of 45 000 and a Km of 0.9 X 10(-4) for CDP. Subunit L2, which did not bind to dATP-Sepharose, was purified by pH 5.2 precipitation followed by chromatography on CM-Sephadex, molecular exclusion HPLC, and DEAE-cellulose. This subunit contained iron and had an apparent Mr of 120 000 by HPLC molecular exclusion chromatography, but showed two bands (Mr 75 000 and Mr 47 000) on SDS-polyacrylamide gel electrophoresis. Neither L1 nor L2 separately had any enzyme activity but when combined they reduced CDP to dCDP.
mesh_terms: D000818:Animals; D004792:Enzyme Precursors / Q000302:isolation & purification*; D007525:Isoelectric Focusing; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008115:Liver Regeneration; D008970:Molecular Weight; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D012264:Ribonucleotide Reductases / Q000302:isolation & purification*
chemical_list: D004792:Enzyme Precursors; D011189:Potassium Chloride; D012264:Ribonucleotide Reductases