Proteolytic enzymes in coastal surface seawater: Significant activity of endopeptidases and exopeptidases
Proteolytic enzymes in coastal surface seawater: Significant activity of endopeptidases and exopeptidases
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DOI：
10.4319/lo.2005.50.2.0722
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发表时间：
2005-03-01
影响因子：
4.5
通讯作者：
Suzuki, S
中科院分区：
文献类型：
--
作者：
Obayashi, Y;Suzuki, S
我们用16种荧光底物分析了近岸表层海水中的蛋白水解酶，包括氨基肽酶、胰蛋白酶、弹力酶和胰凝乳酶。胰酶和胰凝乳酶底物的水解率与氨基肽酶相似或更高。弹性蛋白酶的底物几乎不能被水解。这一结果有力地表明，海水中存在胰蛋白酶型和糜胰酶型内肽酶和氨基肽酶。在以往对水环境中蛋白水解酶的大多数研究中，用荧光底物测量的亮氨酸氨基肽酶活性被用作蛋白水解酶活性的模型。从使用不同的多肽类似物荧光底物的研究结果中，证实了内肽酶的重要性，内肽酶可能在微生物呼吸之前将溶解的蛋白质和多肽缩小为寡肽的关键作用。
We assayed proteolytic enzymes in coastal surface seawater using 16 types of fluorogenic substrates, including those for aminopeptidase, trypsin, elastase, and chymotrypsin. Hydrolysis rates were similar or higher for substrates of trypsin and chymotrypsin than for those of aminopeptidase. Substrates for elastase were hardly hydrolyzed. The results strongly suggest trypsin-type and chymotrypsin-type endopeptidases and aminopeptidases were present in the seawater. In most previous studies of proteolytic enzymes in aquatic environments, leucine-aminopeptidase activity measured using a fluorogenic substrate has been used as a model of proteolytic activity. From the results of this study using various peptide analog fluorogenic substrates, the significance of endopeptidases, which could play a key role in downsizing of dissolved proteins and polypeptides to oligopeptides prior to microbial respiration, was confirmed.