Discovery of two transglutaminases derived from same zymogen for the Streptomyces hygroscopicus and analysis of their formation processes.
BACKGROUND
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.


RESULTS
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.


CONCLUSIONS
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.
Key Laboratory of Industrial Biotechnology (Ministry of Education), School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu, 214122, China.
Wenjing
W
Cui
Xiaoyan
X
Yang
Yueqin
Y
Fang
Shengmin
S
Zhou
Song
S
Liu
Guocheng
G
Du
Kun
K
Du
Jian
J
Chen
Guanjun
G
Tao
Zhemin
Z
Zhou
D001426:Bacterial Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D004792:Enzyme Precursors / Q000737:chemistry / Q000378:metabolism*; D008970:Molecular Weight; D017433:Protein Structure, Secondary; D013302:Streptomyces / Q000201:enzymology*; D011503:Transglutaminases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*
D001426:Bacterial Proteins; D004792:Enzyme Precursors; D011503:Transglutaminases