Pyrrolidonyl peptidase. An enzyme for selective removal of pyrrolidonecarboxylic acid residues from polypeptides.
Pyrrolidonyl peptidase. An enzyme for selective removal of pyrrolidonecarboxylic acid residues from polypeptides.
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吡咯烷酰肽酶。
DOI：
10.1021/bi00842a005
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发表时间：
1968
期刊：
影响因子：
2.9
通讯作者：
R. Armentrout
中科院分区：
文献类型：
--
作者：
R. Doolittle;R. Armentrout
A1.大量天然存在的肽和蛋白质被认为具有吡咯烷酮羧酸（焦谷氨酸）1作为其氨基末端残基（表I），这种情况被认为是由末端N-乙酰氨基（I）或谷氨酰基（III）残基的环化引起的。在这方面，已经发现了一种酶，其将环化肽上的末端谷氨酰胺残基（Messer和Ottesen，1964）。吡咯烷酮基肽（II）也可以在蛋白水解后肽的分离过程中人为地产生，谷氨酰胺终止肽特别易于环化（桑格和汤普森，1953;史密斯等人，1962年）。在这些肽和蛋白质中缺乏n-氨基基团一直是许多这些材料的特征化的主要障碍，因为氨基末端分析，包括逐步降解方法，（Edman和Begg，1967），不能进行。我们最初的目的是寻找一种酶，希望这种酶能使PCA-终止肽中的末端氨基可接近。为此，我们从土壤中分离出一种微生物，它将以游离的五氯苯甲醚作为唯一的碳和氮源生长。当时我们不知道Maruyama和Nomura（1956）以前分离出了一种类似的
A1. large number of naturallyoccurring peptides and proteins are thought to have pyrrolidonecarboxylic acid (pyroglutamic acid) 1 as their amino-terminal residue (Table I), a situation presumedto arise from the cyclization of terminal glutaminyl (I) or glutamyl (III) residues. In this regard, an enzyme has been found which will cyclize terminal glutamine residues on peptides (Messer and Ottesen, 1964). Pyrrolidonyl peptides (II) also can arise artifactually during the isolation of peptides after proteolysis, glutamineterminating peptides being especially liable to cyclize (Sanger and Thompson, 1953; Smyth et al., 1962). The absence of an «-amino group in these peptides and proteins has been a major handicap in thechar-acterization of many of these materials, since aminoterminal analyses, including stepwise degradation methods (Edman and Begg, 1967), cannot be carried out.Our original aim was to look for an enzyme which would open pyrrolidone rings, the hope being that such an enzyme would render terminal amino groups accessible in PCA-terminating peptides. To this end we isolated a microorganism from the soil which will grow on free PCA as the sole source of carbon and nitrogen. At the time we were unaware that Maruyama and Nomura (1956) had previously isolated a similar