These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: C21 steroid side chain cleavage enzyme from porcine adrenal microsomes. Purification and characterization of the 17 alpha-hydroxylase/C17,20-lyase cytochrome P-450.
    Author: Nakajin S, Shinoda M, Haniu M, Shively JE, Hall PF.
    Journal: J Biol Chem; 1984 Mar 25; 259(6):3971-6. PubMed ID: 6608525.
    Abstract:
    The properties and the purity of a cytochrome P-450 (17 alpha-hydroxylase) from porcine adrenal microsomes have been examined following a report that the corresponding enzyme from bovine adrenocortical microsomes is inactive as a 17 alpha-hydroxylase and fails to show a high spin spectrum on addition of substrate, once the enzyme has been purified (Bumpus, J. A., and Dus, K. M. (1982) J. Biol. Chem. 257, 12696-12704). The purity of the porcine enzyme was demonstrated by electrophoresis on polyacrylamide with sodium dodecyl sulfate, immunoelectrophoresis, and NH2-terminal amino acid sequence (16 residues). The pure enzyme shows Mr = 54,000, heme content of greater than 0.8 nmol/nmol of protein, and absorption spectra typical of cytochrome P-450. The enzyme is active with both delta 4 (progesterone) and delta 5 (pregnenolone) substrates as a 17 alpha-hydroxylase and with the corresponding 17 alpha-hydroxysteroids as a C17,20-lyase. All four substrates produce typical type I spectra with the enzyme (so-called high spin form). We conclude that: 1) porcine adrenal microsomes contain a 17 alpha-hydroxylase/C17,20-lyase which is a single protein molecule readily purified to an enzymatically active form; 2) the C17,20-lyase activity is largely suppressed in the microsomes; and 3) the enzyme closely resembles that found in testicular microsomes. We propose that this enzyme be referred to as the adrenal C21 steroid side chain cleavage enzyme.
    [Abstract] [Full Text] [Related] [New Search]