Lebedeva L G, Aleksandrova S S, Basnak'ian A G, Votrin I I
Biokhimiia. 1995 May;60(5):798-804.
Study of the isoenzymatic spectrum of nuclear DNase from rat liver demonstrated that the extracts obtained in the presence of the protease inhibitor, PMSF, contained four polypeptides with molecular masses of 120, 54, 31 and 28 kDa possessing the endo-DNase activity. Long-term storage at -20 degrees C and autodigestion of the nuclei revealed the presence of additional polypeptides with a lower molecular mass and possessing an endo-DNase activity. Treatment of rat liver nuclear extracts with trypsin caused the appearance of an active polypeptide (M(r) 145 kDa). This finding and the multiplicity of endo-DNases of different molecular masses suggest the existence of a precursor possessing a much higher molecular mass. Chromatographic separation of endo-DNases on Sephacryl S-300 revealed three fractions of 400 and more kDa possessing a Ca2+/Mg(2+)-dependent activity, however, only after trypsin treatment.
对大鼠肝脏细胞核DNA酶同工酶谱的研究表明，在蛋白酶抑制剂苯甲基磺酰氟（PMSF）存在的情况下获得的提取物含有四种具有内切DNA酶活性、分子量分别为120、54、31和28 kDa的多肽。在-20℃长期保存以及细胞核的自身消化揭示了存在分子量更低且具有内切DNA酶活性的其他多肽。用胰蛋白酶处理大鼠肝脏细胞核提取物导致出现一种活性多肽（分子量145 kDa）。这一发现以及不同分子量内切DNA酶的多样性表明存在一种分子量高得多的前体。在Sephacryl S - 300上对内切DNA酶进行色谱分离，发现有三个分子量在400 kDa及以上的组分具有Ca2+/Mg(2+)依赖性活性，不过，这仅在胰蛋白酶处理之后。
