• Journal of Microbiology and Biotechnology
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• 제18권12호
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• pp.1938-1944
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• 2008

The procpb gene encoding human procarboxypeptidase B (proCPB, GeneBank access code AJ224866) was cloned and its Pichia expression plasmid, $pPIC9{\alpha}$/hproCPB (9.2 kb), was constructed, in which procpb was under the control of the AOXl promoter and connected to the downstream of the mating factor ${\alpha}$-1 ($MF{\alpha}1$) signal sequence. The plasmid was linearized by digestion with Sacl, and integrated into the genome of P. pastoris strain GS115. By culturing of Pichia transformant on methanol medium, the human proCPB was successfully expressed and secreted into the culture supernatant. Moreover, Western blot analysis of the extracellular proteins showed proCPB bands clearly at a molecular mass of 45 kDa, confirming the expression of proCPB with its right size. The CPB activity reached about 3.5 U/ml and 12.7 U/ml in the flask and fermentor batch cultures of Pichia transformant, respectively. No CPB enzyme activity was found in the intracellular fraction. When the fed-batch cultivation was performed with methanol and glycerol mixture as a feeding medium, the extracellular CPB activity was increased to 42.0 U/ml, which corresponds to a 3.3-fold higher level of CPB activity than that of batch culture. The $K_m$ and $k_{cat}$ values of recombinant human CPB enzyme for hippuryl-$_L$-Arg as a substrate were estimated to be 0.16 mM and $11.93\;sec^{-1}$, respectively.

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2007년도 제48회 학술심포지움 및 추계국제학술대회
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• pp.59.2-59.2
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• 2007

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• 한국미생물·생명공학회지
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• 제36권1호
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• pp.49-54
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• 2008

인간 췌장 유래 pro-carboxypeptidase B(CPB) 유전자를 클로닝한 후 GAL10 promoter 하류에 Saccharomyces cerevisiae mating factor alpha-1 secretion signal $(MF{\alpha}-1)$과 연결하여 $MF{\alpha}1$-pro-CPB를 구축하였다. 구축된 plasmid $pY{\alpha}$-hproCPB(7.72 kb)를 S. cerevisiae 2805에 형질 전환시켰다. 재조합 인간 proCPB(hproCPB)는 galactose 유도로 S. cerevisiae에서 성공적으로 발현되었고, 배양상등액으로 분비되었다. SDS-PAGE와 western blot 분석에 의해, 정제된 hproCPB 단백질이 약 45.9kDa임을 확인하였다 S. cerevisiae $2805/pY{\alpha}$-hproCPB의 발효조 회분배양 시 trypsin 처리에 의해 pro영역을 제거한 후 hCPB의 세포외 활성은 60시간째에 10.16 unit/mL이었다. 또한 재조합 hCPB의 Km 값은 약 0.43 mM 이었다.