中文摘要：

Synechocystis sp。PCC 6803 染色体港口由三个成员，组成的一个 Deg 基因家庭 htrA (degP， slr1204 ) ， hhoA (degQ， sll1679 ) 并且 hhoB (degS， sll1427 ) 。这个工作从 Synechocystis sp 提供了 HhoA， HtrA 和 HhoB 的生物化学的描述。PCC 6803。从 Synechocystis sp 的第一成熟的 HhoA， HhoB 和 HtrA。PCC 6803 在 Escherichia coli 被克隆并且表示同样可溶的 recombinant 他的标注熔化蛋白质。然后， HhoA， HhoB 和 HtrA 的解朊的活动在 vitro 作为底层用酷蛋白，牛的浆液白朊，五 recombinant 色素蛋白和 cyanobacterial phycocyanin 被测试。试验性的结果显示出那 HhoA， HtrA 在酷蛋白，五 recombinant 色素蛋白和 cyanobacterial phycocyanin 上举办了解朊的活动。HhoB 的解朊的活动都没在 vitro 用所有底层被发现，显示在从 Synechocystis sp 的 Deg 朊酶之中的功能的差别。PCC 6803。因此，结果在 vitro 在蛋白质和 phycobiliproteins 的水解作用上显示了 HhoA 和 HtrA 的生物化学的性质，它含有他们可能是朊酶，这在 vivo 在 phycobiliprotein 包含了降级。

英文摘要：

The Synechocystis sp. PCC 6803 genome harbours a Deg gene family consisting of three members, htrA （degP, slr1204）, hhoA （degQ, sll1679） and hhoB （degS, sll1427）. This work provided biochemical characterization of HhoA, HtrA and HhoB from Synechocystis sp. PCC 6803. Firstly mature HhoA, HhoB and HtrA from Synechocystis sp. PCC 6803 were cloned and expressed as soluble recombinant his-tagged fusion protein in Escherichia coli. Then the proteolytic activity of HhoA, HhoB and HtrA was tested using casein, bovine serum albumin, five recombinant chromoproteins and cyanobacterial phycocyanin as substrates in vitro. The experimental results showed that HhoA and HtrA had proteolytic activity on casein, five recombinant chromoproteins and cyanobacterial phycocyanin. No proteolytic activity of HhoB was found using all substrates in vitro, indicating functional difference among Deg proteases from Synechocystis sp. PCC 6803. Therefore, the results indicated the biochemical properties of HhoA and HtrA on hydrolysis of proteins and phycobiliproteins in vitro, which implicated that they were proteases possibly involved in phycobiliprotein degradation in vivo.