Bacteriophage P1 site-specific recombination. Purification and properties of the Cre recombinase protein.

1
The cholesterol side-chain cleavage system of bovine adrenal cortex has been studied using extracts of sonicated mitochondria as source of enzymic activity.

2
The system has been found to be inhibited by carbon monoxide, this inhibition being consistent with competition between carbon monoxide and oxygen for an enzymic site.

3
The inhibition by carbon monoxide is reversed by light, the most effective wavelength being 450 mμ. These results suggest the involvement of a haem-containing protein, ‘P-450’ as the oxygen-binding site in the cholesterol side-chain cleavage system.

4
Attempts have been made to isolate intermediates between cholesterol and pregnenolone. Neither 20α-hydroxycholesterol nor 20α,22-dihydroxycholesterol have been found.

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1432-1033.1967.tb00136.x

The Cholesterol Side-Chain Cleavage System of Bovine Adrenal Cortex

Publisher Summary This review attempts to summarize present knowledge of the degradation and excretion of cholesterol and of factors that influence these processes, i.e., a limited aspect of cholesterol metabolism. No attempt will be made to review the vast literature on the variations in serum cholesterol levels observed under different conditions nor will intermediary bile acid metabolism be discussed in detail. Concerning the conversion of cholesterol to steroid hormones, only the reactions leading to pregnenolone will be discussed. The main pathways for elimination of cholesterol are degradation to bile acids and excretion of neutral sterols in feces. The conversion of cholesterol to steroid hormones is of course of great importance metabolically but is quantitatively rather insignificant.

Present status of research on catabolism and excretion of cholesterol.

Substrate-induced Changes in Visible Absorption and Electron Spin Resonance Properties of Adrenal Cortex Mitochondrial P450

In the present study, we discuss the recent developments in oxysterol research. Exciting results have been reported relating to the involvement of oxysterols in the fields of neurodegenerative disease, especially in Huntington's disease, Parkinson's disease and Alzheimer's disease; in signalling and development, in particular, in relation to Hedgehog signalling; and in cancer, with a special focus on (25R)26-hydroxycholesterol. Methods for the measurement of oxysterols, essential for understanding their mechanism of action in vivo, and valuable for diagnosing rare diseases of cholesterol biosynthesis and metabolism are briefly considered.

/pdf/oxysterol-research-a-brief-review-4gb1g49dvf.pdf

Oxysterol research: a brief review

http://www.jbc.org/content/237/3/703.full.pdf

Amala C. Chaudhuri

Papers

Biosynthesis of pregnenolone from 22-hydroxycholesterol.