Key Laboratory of Industrial Biotechnology (Ministry of Education), School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu, 214122, China.
J Sci Food Agric. 2013 May;93(7):1711-7. doi: 10.1002/jsfa.5956. Epub 2013 Jan 28.
Transglutaminase (TGase) is secreted as a zymogen (Pro-TGase) and is then processed by removal of its N-terminal region through exogenous proteolytic activity. In this study it was discovered that the Pro-TGase from Streptomyces hygroscopicus was also activated by its TGase (processed through exogenous proteolytic activity), resulting in a different active form.
The two TGases exhibited different ionic strengths, hydrophobicities, Km values and stabilities. Circular dichroism spectral analysis showed that the two enzymes had non-identical secondary structures, while liquid chromatography/mass spectrometry (LC-MS) analysis indicated that they differed in molecular mass by 111 Da. The formation of the TGase activated from Pro-TGase by TGase was delayed compared with that of TGase processed through exogenous proteolytic activity. Furthermore, it was found that the TGase activated from Pro-TGase by TGase did not activate Pro-TGase.
Two TGases derived from the same zymogen from S. hygroscopicus were discovered. These two active forms of TGase may be due to different activation processes: one of them is catalysed by its own active TGase, while the other is activated by an exogenous protease.
转谷氨酰胺酶（TGase）以酶原（Pro-TGase）的形式分泌，然后通过外源性蛋白水解活性去除其 N 端区域进行加工。在这项研究中发现，吸水链霉菌的 Pro-TGase 也可以被其自身的 TGase（通过外源性蛋白水解活性进行加工）激活，从而产生不同的活性形式。
两种 TGase 表现出不同的离子强度、疏水性、Km 值和稳定性。圆二色光谱分析表明，两种酶具有不同的二级结构，而液相色谱/质谱（LC-MS）分析表明它们的分子量相差 111 Da。与通过外源性蛋白水解活性加工的 TGase 相比，由 TGase 从 Pro-TGase 激活形成的 TGase 的形成被延迟。此外，还发现由 TGase 从 Pro-TGase 激活的 TGase 本身不能激活 Pro-TGase。
从吸水链霉菌的相同酶原中发现了两种 TGase。这两种 TGase 的活性形式可能是由于不同的激活过程：一种是由自身的活性 TGase 催化，另一种是由外源性蛋白酶激活。
