Purification of terminal deoxynucleotidyl transferase from pig thymus: identification of 42,000 and 57, 000 dalton species.
Terminal deoxynucleotidyl transferase (TdT, EC 2.7.7.31) has been purified 4365-fold from pig thymus. It was further separated into two molecular forms of 57,000 and 45,000 dalton by Sephadex G-100 gel-filtration. The former sedimented at 4.2s through a sucrose gradient, while the latter, at 3.6s. By a SDS-polyacrylamide gel-electrophoresis, their molecular weights were estimated as 57,000 and 42,000 dalton, respectively. Thus each of the large and small pig TdT consists of a single polypeptide of 57,000 or 42,000 dalton and has no subunit structure. These two forms were indistinguishable in antigenicity by a neutralization assay of 42,000 dalton-TdT antibody. The enzymological properties of 42,000 dalton-TdT from pig thymus were very similar to those of calf TdT which has a two-subunits structure.
D000818:Animals; D002417:Cattle; D004253:DNA Nucleotidylexotransferase / Q000302:isolation & purification*; D004254:DNA Nucleotidyltransferases / Q000302:isolation & purification*; D046911:Macromolecular Substances; D008970:Molecular Weight; D013045:Species Specificity; D013552:Swine; D013950:Thymus Gland / Q000201:enzymology*
D046911:Macromolecular Substances; D004254:DNA Nucleotidyltransferases; D004253:DNA Nucleotidylexotransferase