HUMAN-PLASMA PREKALLIKREIN, A ZYMOGEN TO A SERINE PROTEASE THAT CONTAINS 4 TANDEM REPEATS
HUMAN-PLASMA PREKALLIKREIN, A ZYMOGEN TO A SERINE PROTEASE THAT CONTAINS 4 TANDEM REPEATS
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DOI：
10.1021/bi00357a017
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发表时间：
1986-05-06
期刊：
影响因子：
2.9
通讯作者：
DAVIE, EW
中科院分区：
文献类型：
--
作者：
CHUNG, DW;FUJIKAWA, K;DAVIE, EW
人血浆前激肽释放酶的氨基酸序列采用自动Edman降解和基因测序技术相结合的方法进行测定。人血浆前激肽释放酶用三聚氰胺裂解，得到13个均一的多肽，并进行了序列测定。用胰酶进一步消化含碳水化合物的溴化氰多肽，并对含碳水化合物的多肽进行分离和测序。鉴定出五个天冬酰胺连接的碳水化合物结合位点。将Edman降解确定的序列与从λgt11表达文库中分离的cDNA预测的氨基酸序列进行比对。该文库含有从人肝脏Poly(A)RNA中制备的cDNA插入片段。对该基因的分析表明，人血浆前激肽释放酶是由19个氨基酸组成的信号肽前体。在血液中循环的蛋白质的成熟形式是由619个氨基酸组成的单链多肽。血浆前激肽释放酶被XIIa因子通过内部Arg-Ile键的裂解转化为血浆激肽释放酶。血浆激肽释放酶由一条重链(371个氨基酸)和一条轻链(248个氨基酸)组成，这两条链通过二硫键连接在一起。血浆激肽释放酶重链起源于酶原的氨基末端，由4个串联重复序列组成，长度为90或91个氨基酸残基。这些重复序列也与人类因子XI中的序列同源。血浆激肽释放酶的轻链包含酶的催化部分，与丝氨酸蛋白酶的胰酶家族同源。
The amino acid sequence of human plasma prekallikrein was determined by a combination of automated Edman degradation and cDNA sequencing techniques. Human plasma prekallikrein was fragmented with cyanogen bormide, and 13 homogeneous peptides were isolated and sequenced. Cyanogen bromide peptides containing carbohydrate were further digested with trypsin, and the peptides containing carbohydrate were isolated and sequenced. Five asparagine-linked carbohydrate attachment sites were identified. The sequence determined by Edman degradation was aligned with the amino acid sequence predicted from cDNAs isolated from a .lambda.gt11 expression library. This library contained cDNA inserts prepared from human liver poly(A) RNA. Analysis of the cDNA indicated that human plasma prekallikrein is synthesized as a precursor with a signal peptide of 19 amino acids. The mature form of the protein that circulates in blood is a single-chain polypeptide of 619 amino acids. Plasma prekallikrein is converted to plasma kallikrein by factor XIIa by the cleavage of an internal Arg-Ile bond. Plasma Kallikrein is composed of a heavy chain (371 amino acids) and a light chain (248 amino acids), and these 2 chains are held together by a disulfide bond. The heavy chain of plasma kallikrein originates from the amino-terminal end of the zymogen and is composed of 4 tandem repeats that are 90 or 91 amino acid residues in length. These repeat sequences are also homologous to those in human factor XI. The light chain of plasma kallikrein contains the catalytic portion of the enzyme and is homologous to the trypsin family of serine proteases.