Trypsinogens are the inactive precursors of trypsins (EC 3.4.21.4), which are digestive serine proteases. Despite knowing the properties of trypsins from Pacific white shrimp, Penaeus vannamei, the biochemical properties of shrimp trypsinogens including activation mechanisms and kinetics are unknown, due to difficulties isolating them from natural sources. In the present work, we describe the purification and biochemical characterization of four trypsinogen-like isoforms from recombinant P. vannamei trypsinogen, with a special emphasis on understanding its activation kinetics. The major trypsinogen-like isoform had an apparent molecular mass of 29 kDa. The other three forms of recombinant trypsinogen were: an N-glycosylated form of 32 kDa, a possibly O-glycosylated form of 41 kDa, and a likely double-chain form with a subunit of 23 kDa. The autoactivation profile of three-recombinant trypsinogen-like isoforms showed increased trypsin activity at a rate that was higher than that of bovine trypsinogen. This confirms the hypothesis proposed in the literature of a rapid trypsinogen autoactivation in the absence of aspartates in the activation peptide as it is for P. vannamei trypsinogen.

胰蛋白酶原是胰蛋白酶的无活性前体（EC 3.4.21.4），是消化性丝氨酸蛋白酶。尽管知道太平洋白虾南美白对虾的胰蛋白酶的特性，但是由于难以将虾胰蛋白酶原与自然来源分离，所以其胰蛋白酶原的生化特性（包括激活机制和动力学）尚不清楚。在本工作中，我们描述了重组南美白对虾中四种胰蛋白酶原样亚型的纯化和生化特性胰蛋白酶原，特别强调了解其激活动力学。主要的胰蛋白酶原样亚型具有29kDa的表观分子量。重组胰蛋白酶原的其他三种形式是：32 kDa的N-糖基化形式，41 kDa的O-糖基化形式和亚基23 kDa的双链形式。三重组胰蛋白酶原样亚型的自激活谱显示出胰蛋白酶活性的增加速率高于牛胰蛋白酶原。这证实了在文献中提出的假设，即在激活肽中不存在天冬氨酸的情况下，胰蛋白酶原会快速自动激活，就像南美白对虾胰蛋白酶原一样。