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首页> 外文期刊>Infection and immunity >Proline iminopeptidase from the outer cell envelope of the human oral spirochete Treponema denticola ATCC 35405.
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Proline iminopeptidase from the outer cell envelope of the human oral spirochete Treponema denticola ATCC 35405.

机译：脯氨酸亚肽酶来自人类口服螺旋体密螺旋体密螺旋体ATCC 35405的外层细胞包膜。

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Certain periodontopathic organisms have been shown to exhibit high activity of proline iminopeptidase (PIPase). The human oral spirochete Treponema denticola ATCC 35405 was found to contain an easily extractable, novel PIPase (EC 3.4.11.5), which was purified to a sodium dodecyl sulfate- polyacrylamide gel electrophoresis-pure form by means of fast protein liquid chromatographic procedures. The range of the minimum monomeric molecular mass (280 amino acid residues) of the PIPase, based on amino acid analysis, was 30.35 to 30.39 kDa, but the likely in vivo form of the enzyme is a tetramer (minimum mass, 120.2 to 120.4 kDa). The molecular masses based on laser desorption mass spectrometry were 36.058 kDa for the monomer and 72.596 kDa for a dimer. The PIPase cleaves specifically the Pro-Y bond in dipeptides where Y is preferably Arg or Lys. Pro-Gln, Pro-Asn, and Pro-Ala were also good substrates, while Pro-Glu was hydrolyzed slowly and Pro-Asp was not hydrolyzed at all. Tripeptides were poor substrates or were not hydrolyzed (an exception was Pro-Gly-Gly, which cleaved at a moderate rate). Larger molecules, such as poly-L-Pro, were not hydrolyzed. The T. denticola enzyme can be regarded as a true PIPase, since replacing Pro in Pro-Y with other amino acid residues resulted in no hydrolysis. The activity of the PIPase may depend on an active carboxyl group and on an active seryl residue but not on metal cations. Diethylpyrocarbonate inactivated the enzyme in a reaction that was not reversible upon addition of NH2OH. The enzyme contains a relatively large percentage (ca. 15%) of proline residues. The dominance of the PIPase activity among aminopeptidase activities present in T. denticola and the proposed location of the enzyme in the outer cell envelope suggest that it has a vital function in the propagation of the cells within their biological niche (inflamed human periodontal tissues). The biologic role of the PIPase may be envisaged as in the termination of the overall peptidolytic cascade (liberating free proline and other amino acids), whereby host tissue proteins and peptides are first processed and inactivated by other peptidases possibly present within the same confines as the PIPase.
机译：已经显示某些牙周病生物显示出脯氨酸亚肽酶（PIPase）的高活性。发现人的口腔螺旋体树状密螺旋体ATCC 35405含有易于提取的新型PIPase（EC 3.4.11.5），可通过快速蛋白质液相色谱法将其纯化为十二烷基硫酸钠-聚丙烯酰胺凝胶电泳纯形式。根据氨基酸分析，PIPase的最小单体分子量（280个氨基酸残基）范围为30.35至30.39 kDa，但该酶的体内可能形式为四聚体（最小质量为120.2至120.4 kDa） ）。基于激光解吸质谱的分子质量对于单体是36.058kDa，对于二聚体是72.596kDa。 PIPase特异性切割二肽中的Pro-Y键，其中Y优选为Arg或Lys。 Pro-Gln，Pro-Asn和Pro-Ala也是良好的底物，而Pro-Glu则缓慢水解，而Pro-Asp则根本不水解。三肽是较差的底物或没有被水解（Pro-Gly-Gly是例外，它以中等速率裂解）。较大的分子，例如聚-L-Pro，没有被水解。可以将T. denticola酶视为真正的PIPase，因为用其他氨基酸残基取代Pro-Y中的Pro不会导致水解。 PIPase的活性可能取决于活性羧基和活性Seryl残基，而不取决于金属阳离子。焦碳酸二乙酯在添加NH2OH后不可逆的反应中使酶失活。该酶含有相对较大百分比（约15％）的脯氨酸残基。 P.pticase活性在T.denticola中存在的氨肽酶活性中占主导地位，并且该酶在细胞外层被膜中的位置表明，它在细胞生物学位点（发炎的人类牙周组织）内的繁殖中具有至关重要的作用。可以设想PIPase的生物学作用是终止整个肽水解级联反应（释放游离脯氨酸和其他氨基酸），从而首先将宿主组织蛋白和肽类加工并通过可能存在于与该蛋白相同的范围内的其他肽酶进行灭活。 PIPase。

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