Kaneda T, Kuroda S, Koiwai O, Yoshida S
J Biochem. 1981 Nov;90(5):1421-7. doi: 10.1093/oxfordjournals.jbchem.a133608.
Terminal deoxynucleotidyl transferase [EC 2.7.7.31] has been purified 4,365-fold from pig thymus. It was further separated into two molecular forms of 57,000 and 45,000 daltons by Sephadex G-100 gel-filtration. The former sedimented at 4.2S through a sucrose gradient, while the latter sedimented at 3.6S. By sodium dodecyl sulfate-polyacrylamide gel-electrophoresis, their molecular weights were estimated at 57,000 and 42,000 daltons, respectively. Thus, the large and small pig terminal deoxynucleotidyl transferases both consist of a single polypeptide of 57,000 and 42,000 daltons and have no subunit structure. These two forms were indistinguishable in antigenicity as examined by a neutralization assay with an anti-calf terminal deoxynucleotidyl transferase antibody. The enzymatic properties of 42,000-dalton terminal deoxynucleotidyl transferase from pig thymus were very similar to those of the calf enzyme, which has a two-subunit structure.
末端脱氧核苷酸转移酶[EC 2.7.7.31]已从猪胸腺中纯化了4365倍。通过Sephadex G - 100凝胶过滤进一步将其分离为分子量分别为57,000和45,000道尔顿的两种分子形式。前者在蔗糖梯度中沉降系数为4.2S，而后者沉降系数为3.6S。通过十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳，它们的分子量分别估计为57,000和42,000道尔顿。因此，大、小两种猪末端脱氧核苷酸转移酶均由一条分子量为57,000和42,000道尔顿的单一多肽组成，且无亚基结构。用抗小牛末端脱氧核苷酸转移酶抗体进行中和试验检测发现，这两种形式在抗原性上无法区分。猪胸腺中42,000道尔顿末端脱氧核苷酸转移酶的酶学性质与具有双亚基结构的小牛酶非常相似。
