Dipeptidyl peptidase IV from human serum: Purification, characterization, and N-terminal amino acid sequence
Dipeptidyl peptidase IV from human serum: Purification, characterization, and N-terminal amino acid sequence
复制标题
DOI：
10.1093/oxfordjournals.jbchem.a022130
复制
发表时间：
1998-08-01
影响因子：
2.7
通讯作者：
Fujimoto, Y
中科院分区：
文献类型：
--
作者：
Iwaki-Egawa, S;Watanabe, Y;Fujimoto, Y
将正常人血清中的二肽基肽酶IV(DPP IV)纯化了14,400倍，得率为25%，纯化后的酶分子量约为110,000，与人肾膜结合的DPP IV几乎相同。这两种酶在底物专一性、对抑制剂的敏感性、与抗大鼠肾DPP IV抗体的交叉反应、与腺苷脱氨酶的结合能力等方面都没有发现差异。然而，血清DPP IV的N-末端氨基酸序列缺少膜结合酶的跨膜区，从该序列预测的N-末端的第39位丝氨酸开始。这些结果表明，膜结合的DPP IV在释放到血清中时失去了跨膜结构域，并且它与腺苷脱氨酶的结合不需要质膜上的结构。
Dipeptidyl peptidase IV (DPP IV) in normal human serum was purified 14,400-fold with a 25% yield to homogeneity, The molecular weight of the purified enzyme was approximately 110,000 on SDS-PAGE, almost the same as that of human kidney membrane-bound DPP IV. No difference was found between the two enzymes enzymologically and immunologically, either in substrate specificity, susceptibility to inhibitors, or cross-reactivity with an anti-rat kidney DPP IV antibody, or in their ability to bind adenosine deaminase. However, the N-terminal amino acid sequence of serum DPP IV lacked the transmembrane domain of the membrane-bound enzyme and started at the 39th position, serine, from the N-terminus predicted from the cDNA nucleotide sequence. These results suggest that membrane-bound DPP IV loses its transmembrane domain upon release into the serum, and that its structure on the plasma membrane is not required for its binding to adenosine deaminase.