Testicular Angiotensin-Converting Enzyme with Different Glycan Modification: Characterization on Glycosylphosphatidylinositol-Anchored Protein Releasing and Dipeptidase Activities
Testicular Angiotensin-Converting Enzyme with Different Glycan Modification: Characterization on Glycosylphosphatidylinositol-Anchored Protein Releasing and Dipeptidase Activities
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DOI：
10.1093/jb/mvn148
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发表时间：
2009-01-01
影响因子：
2.7
通讯作者：
Kinoshita, Taroh
中科院分区：
文献类型：
--
作者：
Kondoh, Gen;Watanabe, Hitomi;Kinoshita, Taroh
我们以前已经发现，血管紧张素转换酶（ACE）进行GPI锚定蛋白释放活性（GPIase）以及二肽酶活性。睾丸ACE（tACE）是雄性生殖细胞特有的同工酶，在雄性受精过程中起着重要作用.该同工酶的氨基末端区域不同于体细胞同工酶（sACE），并且含有潜在的O-连接糖基化位点。通过计算机模拟预测后的多重诱变，分配获得O-聚糖的氨基酸残基。比较了O-聚糖无效突变体和野生型分子的GPIase和二肽酶活性，但没有发现差异。此外，野生型tACE在两种不同细胞（COS 7和CHO）中产生并比较了其活性。CHO衍生分子的GPI酶活性明显高于COS 7，但二肽酶活性不明显。这两种分子对神经氨酸酶和O-糖苷酶的敏感性以及糖基化谱有很大差异。此外，与神经氨酸酶和O-糖苷酶的连续二聚体对两种分子的GPIase活性没有影响，表明唾液酸化和O-聚糖的存在对tACE酶活性没有影响，而聚糖组调节GPIase活性。
We have previously found that the angiotensin-converting enzyme (ACE) carries GPI-anchored protein releasing activity (GPIase) as well as dipeptidase activity. Testicular ACE (tACE), the male germinal specific isozyme, plays a crucial role in male fertilization. The amino-terminal region of this isozyme is different from that of somatic isozyme (sACE) and contains potential O-linked glycosylation sites. By multiple mutagenesis after an in silico prediction, amino acid residues acquiring O-glycans were assigned. Both GPIase and dipeptidase activities were compared between O-glycan null mutant and wild-type molecules, but no differences were found. Furthermore, the wild-type tACE was produced in two different cells (COS7 and CHO) and its activities compared. The GPIase activity, but not dipeptidase, was apparently higher for CHO-derived molecule than COS7. Sensitivity to neuraminidase and O-glycosidase digestions and the profile of glycosylation were quite different between these two molecules. Moreover, serial digestions with neuraminidase and O-glycosidase have no influence on GPIase activity of both molecules, suggesting that the sialylation and the presence of O-glycan has no influence on tACE enzyme activities, while the set of glycans modulate GPIase activity.