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ISSN
1672-9145
Acta Biochim Biophys Sin
2004, 36(9): 583–588
CN 31-1940/Q
The Role of Propeptide in the Refolding of Human Group IB
Phospholipase A2
Hong-Qiang CHENG1 and Gen-Jun
XU1,2*
1Institute of
Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences,
Chinese Academy of Sciences, Shanghai 200031, China; 2College of
Life Science, Zhejiang University of Sciences, Hangzhou 310033, China
Abstract Human group IB phospholipase
A2 (IB-PLA2) and its zymogen (proIB-PLA2) were purified from E. coli. Refolding was carried out by
diluting the denatured forms of both IB-PLA2 and
proIB-PLA2 with renaturation buffer in which the disulfide bonds were
completely reduced. The refolding yield of proIB-PLA2 was
increased by about 50% over that of the mature enzyme. The refolding of IB-PLA2 usually produced aggregates under normal conditions, as determined
by light scattering. In addition, the unfolding experiments showed that the
mature enzyme was more stable than the proenzyme toward denaturants in the
presence of DTT. Results suggested that the N-terminal sequence rather than its
conformation of human proIB-PLA2 played an important role in
the refolding process.
Key words human group IB phospholipase A2 (IB-PLA2); refolding; first disulfide bond; propeptide
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Received: May 13, 2004 Accepted: July 15, 2004
This work was supported by a grant from the National Natural Science
Foundation of China (No. 39930060)
*Corresponding author: Tel, 86-21-54921257; Fax, 86-21-54921257;
E-mail, [email protected]