Kikkawa Y, Yamanaka N, Tada J, Kanamori N, Tsumura K, Hosoi K
Department of Physiology, Tokushima University School of Dentistry, Japan.
Biochim Biophys Acta. 1998 Jan 15;1382(1):55-64. doi: 10.1016/s0167-4838(97)00144-1.
Four members of the tissue kallikrein family, mK1, mK9, mK13, and mK22, all of which exhibit extensive homology in amino acid sequence among themselves, were obtained from the submandibular gland of ICR mice and examined for their ability to cleave prorenin. Tissue kallikrein mK13 was confirmed to be a prorenin-converting enzyme; and mK9, which was earlier shown to be an EGF-binding protein, was found to cleave mouse Ren 2 prorenin specifically and convert it to mature renin with an activity of approximately 1/10 of that of mK13. With the same substrate, mK22 (beta-NGF endopeptidase) gave two products, renin and arginyl-renin; whereas mK1 (true tissue kallikrein) did not process it at all. The endoproteolytic activity of tissue kallikreins was examined with various peptide-MCA substrates. The substrates contained three key structures; X(Y)-Arg-Arg, X(Y)-Lys-Arg and X-Lys-Lys motifs (where X and Y are hydrophilic and hydrophobic amino acids, respectively). We found that mK1, mK9 and mK13 preferentially cleaved the former two types of substrate, except Y-Arg-Arg-MCA. The substrate X-Lys-Lys-MCA was hardly cleaved by these three tissue kallikreins but was preferentially cleaved by mK22. The four tissue kallikreins seem to have the ability to process precursor proteins containing a pair of basic amino acid residues; the specificities of three of the enzymes (mK1, mK9 and mK13) were similar to each other but were different from that of mK22.
从ICR小鼠的下颌下腺中获得了组织激肽释放酶家族的四个成员，即mK1、mK9、mK13和mK22，它们彼此之间在氨基酸序列上具有广泛的同源性，并检测了它们切割血管紧张素原的能力。组织激肽释放酶mK13被证实是一种血管紧张素原转化酶；而mK9，早期被证明是一种表皮生长因子结合蛋白，被发现能特异性切割小鼠Ren 2血管紧张素原，并将其转化为成熟肾素，其活性约为mK13的1/10。对于相同的底物，mK22（β-神经生长因子内肽酶）产生两种产物，即肾素和精氨酰-肾素；而mK1（真正的组织激肽释放酶）根本不处理它。用各种肽-MCA底物检测了组织激肽释放酶的内切蛋白水解活性。这些底物包含三个关键结构：X(Y)-Arg-Arg、X(Y)-Lys-Arg和X-Lys-Lys基序（其中X和Y分别为亲水和疏水氨基酸）。我们发现，mK1、mK9和mK13优先切割前两种类型的底物，但Y-Arg-Arg-MCA除外。底物X-Lys-Lys-MCA几乎不被这三种组织激肽释放酶切割，但优先被mK22切割。这四种组织激肽释放酶似乎都有处理含有一对碱性氨基酸残基的前体蛋白的能力；其中三种酶（mK1、mK9和mK13）的特异性彼此相似，但与mK
