Structural studies of bovine liver rhodanese. I. Isolation and characterization of two active forms of the enzyme.
نویسندگان
چکیده
Crystalline bovine liver rhodanese, prepared by ammonium sulfate and pH precipitation, has been shown to be comprised of two fully active components present in approximately equal amounts which are separable by polyacrylamide gel electrophoresis and by ion exchange chromatography. The two rhodanese forms, designated A and B on the basis of their order of elution from columns of DEAE-Sephadex, are not in equilibrium nor do they represent free enzyme and an enzyme-substrate complex. Furthermore, the two rhodanese species are identical with respect to kinetic parameters, amino acid composition, NHz-terminal amino acid, sulfhydryl content, tryptic peptide maps, and molecular weight. Both forms exhibit equal activity toward fl-mercaptopyruvate and utilize this sulfur donor at an efficiency of about 1% that of thiosulfate. Although no chemical or physical basis for the difference between the two rhodanese forms has been found as yet, a new, milder method for the preparation of the enzyme yields a preponderance of rhodanese A (85 to 90%). This, considered together with the elution characteristics of rhodaneses A and B, suggests that rhodanese B may arise during the course of the purification by deamidation of the A form.
منابع مشابه
Molecular cloning, sequencing and characterization of cDNA to rat liver rhodanese, a thiosulphate sulphurtransferase.
Rhodanese (EC 2.8.1.1), a mitochondrial thiosulphate sulphurtransferase, is involved in the formation of iron-sulphur complexes and cyanide detoxification. By screening a rat liver cDNA library with oligonucleotide probes complementary to portions of the published bovine rhodanese peptide sequence, rat rhodanese cDNA clones were obtained and sequenced. Comparison of the rat rhodanese cDNA open ...
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ورودعنوان ژورنال:
- The Journal of biological chemistry
دوره 246 8 شماره
صفحات -
تاریخ انتشار 1971