The N-terminal hydrophobic domain of P450c21 is required for membrane insertion and enzyme stability

L. C. Hsu, M. C. Hu, H. C. Cheng, J. C. Lu, B. C. Chung

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

Microsomal cytochromes P-450 are known to be integrated into smooth endoplasmic reticulum through their hydrophobic sequences located at the N termini. The length requirement of the membrane insertion signal was determined by the generation of six plasmids encoding mutant P450c21 that lacked various portions of the N-terminal hydrophobic domains. When they were transcribed and translated in vitro in the presence of endoplasmic reticulum membranes, mutant protein lacking more than a third of the first hydrophobic domain gradually lost the ability to insert into the membrane and stayed mostly in the soluble fraction when the first N-terminal hydrophobic domain was removed. The steady-state amount of the truncated proteins was progressively reduced in parallel to the extent of their N-terminal deletions, due to their fast degradation. This process was accompanied by a decrease in the enzymatic activity. Therefore, the first hydrophobic domain of P450c21 not only serves as a membrane targeting and anchoring domain, but it is also important for the in vivo protein stability.

Original languageEnglish
Pages (from-to)14682-14686
Number of pages5
JournalJournal of Biological Chemistry
Volume268
Issue number20
Publication statusPublished - Jan 1 1993

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Enzyme Stability
Membranes
Enzymes
Smooth Endoplasmic Reticulum
Protein Stability
Mutant Proteins
Endoplasmic Reticulum
Cytochrome P-450 Enzyme System
Die casting inserts
Membrane Proteins
Plasmids
Proteins
Degradation

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Hsu, L. C., Hu, M. C., Cheng, H. C., Lu, J. C., & Chung, B. C. (1993). The N-terminal hydrophobic domain of P450c21 is required for membrane insertion and enzyme stability. Journal of Biological Chemistry, 268(20), 14682-14686.

The N-terminal hydrophobic domain of P450c21 is required for membrane insertion and enzyme stability. / Hsu, L. C.; Hu, M. C.; Cheng, H. C.; Lu, J. C.; Chung, B. C.

In: Journal of Biological Chemistry, Vol. 268, No. 20, 01.01.1993, p. 14682-14686.

Research output: Contribution to journalArticle

Hsu, LC, Hu, MC, Cheng, HC, Lu, JC & Chung, BC 1993, 'The N-terminal hydrophobic domain of P450c21 is required for membrane insertion and enzyme stability', Journal of Biological Chemistry, vol. 268, no. 20, pp. 14682-14686.
Hsu, L. C. ; Hu, M. C. ; Cheng, H. C. ; Lu, J. C. ; Chung, B. C. / The N-terminal hydrophobic domain of P450c21 is required for membrane insertion and enzyme stability. In: Journal of Biological Chemistry. 1993 ; Vol. 268, No. 20. pp. 14682-14686.
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