Pepstatin-Insensitive Carboxyl Proteinase : Glutamic Proteinase

众所周知，羧基蛋白酶通常被胃抑素、丹和EPNP抑制，它们的催化残基由两个天冬氨酸残基组成。因此，羧基蛋白水解酶被称为天冬氨酸蛋白酶。这些酶在一级结构和三级结构上都具有高度的同源性。我们从真菌、细菌和嗜热菌中分离出了新的羧基蛋白酶，因为它们对胃抑素、DAN和EPNP不敏感。这些酶暂时被命名为胃抑素不敏感的羧基蛋白酶。在我们的一项研究中，我们已经确定了木质青霉菌的羧基蛋白酶B(由204个氨基酸组成)的一级结构，其中一个催化残基被明确为Glu-53。这是有关谷氨酸蛋白水解酶的首次报道，推测胃抑素不敏感的羧基水解酶可能不是天冬氨酸蛋白酶，而是谷氨酸蛋白酶。为了证实这种可能性，我们研究了一种胃抑素不敏感的…假单胞菌产生较多的羧基蛋白酶。第101号，这是第一个从原核细胞中分离到的羧基蛋白酶。我们确定了该酶的一级结构是由363个氨基酸残基和一个二硫键组成的单一多肽。已阐明的一级结构与迄今报道的天冬氨酸蛋白酶的一级结构没有任何同源结构。此外，在天冬氨酸蛋白酶的活性中心没有观察到保守的结构-Asp*-Thr-Gly-。在我们尝试将抑制剂用于活性中心的研究中，我们从北孢子霉中分离到一个新的抑制剂。55号。经鉴定为N-异戊基-酪氨酰-亮氨酰-酪氨酸，命名为酪抑素。酪抑素对Pseuomonas sp.的化学计量胃抑素不敏感的羧基蛋白酶有抑制作用。用酪抑素或其衍生物鉴定假单胞菌羧基蛋白酶催化残基的进一步研究正在进行中。1)胃蛋白酶抑制剂胃抑素；2)重氮乙酰-DL-去亮氨酸甲酯；3)EPNP，1，2-epou-3-(对-硝基苯氧基)丙烷。较少

It is well known that carboxyl proteases are commonly inhibited by pepstatin^<1)> , DAN^<2)> and EPNP^<3)> , and their catalytic residues are composed of two aspartic residues. Thus, carboxyl proteases are termed aspartic proteases. These enzymes are highly homologous in both the primary and tertiary structures.We have isolated novel carboxyl proteases from fungi, bacteria and also thermophilic bacteria based on their insensitivities to pepstatin, DAN and EPNP. These enzymes were tentatively named pepstatin-insensitve carboxyl proteases. In one of our studies, the primary structure of carboxyl protease B ( consisting of 204 aminb acids) from a fungus Scytalidium lignicolum has been established, one of the catalytic residues of which was clarified to be Glu-53. This is the first report on glutamic protease.It seemed probable that the pepstatin-insensitive carboxyl proteases are not aspartic proteases but glutamic proteases. To confirm this possibility, we studied a pepstatin-insensitive … More carboxyl protease from Pseudomonas sp. No. 101, which is the the first carboxyl protease isolated from prokaryote cells. We determined the primary structure of the enzyme as a single polypeptide composed of 363 amino acid residues with one disulfide bridge. The elucidated primary structure does not have any homologous structure to those of aspartic proteases reported so far. Moreover, the well-conserved structure, -Asp*-Thr-Gly- in the active center of aspartic proteases was not observed.In our attempt to use inhibitor in the study of active center we isolated a novel inhibitor from Kitasatosporia sp. No. 55. It was identified as N-isovaleryl-tyrosyl-leucyl-tyrosinal and named it tyrostatin. Tyrostatin was found to inhibit stoichiometrically pepstatin- insensitive carboxyl proteinases of Pseuomonas sp. No. 101.Further study on identification of the catalytic residues of Pseudomonas carboxyl protease using tyrostatin or its derivatives is now in progress. 1 ) pepstatin, pepsin inhibitor; 2) DAN, diazoacetyl-DL-norleucine methylester; 3) EPNP, 1,2-epou-3-(p- nitrophenoxy) propane. Less