Yoshimoto T, Kita T, Ichinose M, Tsuru D
J Biochem. 1982 Jul;92(1):275-82. doi: 10.1093/oxfordjournals.jbchem.a133924.
Dipeptidyl aminopeptidase IV [EC 3.4.14.5] was purified from the water extract of porcine pancreas acetone powder by a series of column chromatographies on DEAE-Sephadex and gel filtration on Sephadex G-200, and was finally subjected to gel filtration on Toyo-pearl in the presence of 1% deoxycholate. The purified enzyme was homogeneous as judged by disc gel and SDS gel electrophoreses. The enzyme was most active at pH 8.0 with Gly-Pro-beta-naphthylamide (Gly-Pro-2-NNap) as the substrate and hydrolyzed peptide bonds involving the carboxyl group of prolyl residues penultimate to unprotected termini. The enzyme was completely inactivated by diisopropyl phosphorofluoridate (DFP), but only slightly inhibited by phenylmethane sulfonylfluoride (PMSF), SH-blocking reagents and metal chelators. The isoelectric point of the enzyme was 4.8, and the molecular weight was estimated to be 230,000 by gel filtration on Sephadex G-200 and 115,000 by sodium dodecyl sulfate (SDS) gel electrophoresis, suggesting that the enzyme is composed of two identical subunits.
二肽基肽酶IV [EC 3.4.14.5] 是从猪胰腺丙酮粉的水提取物中，通过在DEAE-葡聚糖上进行一系列柱色谱以及在葡聚糖G-200上进行凝胶过滤而纯化得到的，最后在1%脱氧胆酸盐存在的条件下在东洋珠上进行凝胶过滤。通过圆盘凝胶电泳和SDS凝胶电泳判断，纯化后的酶是均一的。该酶以甘氨酰-脯氨酰-β-萘酰胺（Gly-Pro-2-NNap）为底物时，在pH 8.0下活性最高，可水解涉及未保护末端倒数第二个脯氨酰残基羧基的肽键。该酶被二异丙基氟磷酸酯（DFP）完全灭活，但仅被苯甲基磺酰氟（PMSF）、SH阻断剂和金属螯合剂轻微抑制。该酶的等电点为4.8，通过在葡聚糖G-200上进行凝胶过滤估计分子量为230,000，通过十二烷基硫酸钠（SDS）凝胶电泳估计分子量为115,000，这表明该酶由两个相同的亚基组成。
