Investigation of steroidogenic cytochromes P-450 will be continued with further characterization of the active sties of the six steroidogenic cytochromes P-450 (aromatase, 11B- hydroxylase, C27 side-chain cleavage, 21-hydroxylase, 17a- hydroxylase and C21 side-chain cleavage). Characterization will be achieved by active site-affinity-labelling using bromoacetoxy- steroids that bind specifically to the active sites of these enzymes. The enzymes are presently being subjected to the combined approaches of microsequencing and genetic cloning; these procedures will be continued until the complete sequences of these porcine enzymes are determined; this information is vital to interpretation of active site labelling. The organization of steroidogenic proteins (P-450, P-450 reductase, cytochrome b5) within testicular and adrenal microsomes from pig and rat will be studied to characterize a pregnenolone-binding protein, to cross- link cytochromes P-450 to adjacent microsomal proteins and to determine the arrangement of these proteins by immunoelectron microscopy. These studies of microsomal proteins will make use of well characterized antibodies that cross-react with the above proteins from pig and rat microsomes.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
1R01DK038363-01A1
Application #
3237717
Study Section
Biochemical Endocrinology Study Section (BCE)
Project Start
1988-05-01
Project End
1991-04-30
Budget Start
1988-05-01
Budget End
1989-04-30
Support Year
1
Fiscal Year
1988
Total Cost
Indirect Cost
Name
University of New South Wales
Department
Type
DUNS #
751020900
City
Sydney
State
Country
Australia
Zip Code
2052
Hall, P F (1991) Cytochrome P-450 C21scc: one enzyme with two actions: hydroxylase and lyase. J Steroid Biochem Mol Biol 40:527-32