Secretion of an aminopeptidase during transition of third- to fourth-stage larvae of Ascaris suum.
Secretion of an aminopeptidase during transition of third- to fourth-stage larvae of Ascaris suum.
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DOI：
10.2307/3284267
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发表时间：
1997-10
期刊：
影响因子：
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通讯作者：
M. L. Rhoads;R. Fetterer;J. Urban
中科院分区：
文献类型：
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作者：
M. L. Rhoads;R. Fetterer;J. Urban
在猪蛔虫L3 ~ L4幼虫期体外培养液中鉴定了蛋白酶活性。具有未阻断n端的荧光肽底物被特异性水解，表明氨基肽酶活性；优选末端精氨酸残基。培养液不能水解n端阻断的荧光肽底物（内多肽酶底物）。金属蛋白酶抑制剂1,10-菲罗啉和氨基肽酶抑制剂阿马司他汀和百司他汀抑制了氨基肽酶活性；AEBSF（丝氨酸蛋白酶抑制剂）、z - fe -ala- fmk和E-64（半胱氨酸蛋白酶抑制剂）和pepstatin A（天冬氨酸蛋白酶抑制剂）对活性影响不大。用蔗糖密度梯度离心法在293 kDa下测定了氨基肽酶的表观分子量。氨基肽酶的酸性等电点为4.7。氨基肽酶的分泌高峰与蜕皮有一定的时间性关系，表明该蛋白酶在这一复杂过程中起着一定的作用。
Protease activity was identified in culture fluids collected during in vitro development of L3 to L4 larval stages of Ascaris suum. Fluorogenic peptide substrates with unblocked N-termini were specifically hydrolyzed indicating aminopeptidase activity; a terminal arginyl residue was preferred. Culture fluids did not hydrolyze fluorogenic peptide substrates with blocked N-termini (endopeptidase substrates). The aminopeptidase activity was inhibited by 1,10-phenanthroline (metalloprotease inhibitor) and by amastatin and bestatin (aminopeptidase inhibitors); AEBSF (serine protease inhibitor), Z-phe-ala-FMK and E-64 (cysteine protease inhibitors), and pepstatin A (aspartyl protease inhibitor) had little effect on activity. The apparent molecular weight of the aminopeptidase was estimated by sucrose density gradient centrifugation at 293 kDa. The aminopeptidase displayed an acidic isoelectric point of 4.7. The peak secretion of the aminopeptidase was temporally associated with molting and suggests a function for the protease in this complex process.