Purification of Terminal Deoxynucleotidyl Transferase of 60,000 Dalton from Mammalian Thymus and Thymona by Immunoadsorbent Column and Comparison of Peptide Structures
There are many discrepancies in the molecular weight of terminal deoxynucleotidyl transferase (TdT) reported, e.g. 32- and 79-kilodalton(k) forms1–7, and also in the enzyme structure, i.e. two-sub-unit form (the α and β subunits)1–3 or single polypeptide form4–7. However, it has not been established yet whether these differences reflect species- or tissue-specificities of the enzyme, or are due simply to the proteolytic degradation during purification process. In order to clarify this issue, we have developed a new, rapid purification method, immunoadsorbent column chromatography, which is suitable to purify TdT’s from limited amounts of tissues such as rodent thymus8. Furthermore, the enzyme proteins from various species of mammals were compared by two-dimensional peptide mapping.
KeywordsTryptic Peptide Terminal Deoxynucleotidyl Transferase Enzyme Protein Single Polypeptide Normal Thymus
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