PMID: 807237Jun 17, 1975

Comparison of 12alpha-hydroxylation of oxygenated 5alpha-cholestanes and allochenodeoxycholate with rat liver microsomes

M M Mui, W H Elliott


[5alpha,6alpha-3H2]-5alpha-Cholestane-3alpha,7alpha-diol (A), (25 R)-3alpha,7alpha-dihydroxyl-[5alpha,6alpha-3H2]-5alpha--cholestan-26-oic acid (B),(25R)-[5alpha,6alpha-3H2]stane-3alpha,7alpha-26-triol (C), and [3beta-3H]allochenodeoxycholic acid (D) were prepared, characterized, and studied with a rat liver microsomal preparation fortified with 1 mM NADPH. The 12alpha-hydroxylated product formed from each of these substrates was identified by isotopic dilution; the relative reactivity of the four substrates was (A) 100; (B) 87; (C) 135; and (D) 40. The microsomal system showed a requirement for added NADPH and other properties similar to those shown for 12alpha-hydroxylation of 7alpha-hydroxycholest-4-en-3-one, which is ultimately converted to cholic acid. Since the coplanar 5alpha-cholestane-3alpha,7alpha-diol is virtually superimposable upon 7alpha-hydroxycholest-4-en-3-one, and the enzymic requirements are comparable, it is suggested that a single enzyme system may be responsible for 12alpha-hydroxylation of these substrates.


Jul 2, 1973·European Journal of Biochemistry·I Björkhem, J Gustafsson
Jul 2, 1973·European Journal of Biochemistry·I BjörkhemK Wikvall
Oct 1, 1973·Biochemical and Biophysical Research Communications·C BernhardssonK Wikvall
Oct 1, 1970·European Journal of Biochemistry·T Cronholm, G Johansson
May 23, 1972·European Journal of Biochemistry·I Björkhem
Sep 1, 1972·Steroids·S Y Kamat, W H Elliott
Jan 1, 1971·European Journal of Biochemistry·I Björkhem, J Gustafsson
Jan 1, 1965·Annual Review of Biochemistry·P TALALAY

Related Concepts

Edetic Acid, Sodium Salt
Microsomes, Liver
Mitochondria, Liver
Plasma Protein Binding Capacity
Steroid Hydroxylases

Trending Feeds


Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Alzheimer's Disease: MS4A

Variants within the membrane-spanning 4-domains subfamily A (MS4A) gene cluster have recently been implicated in Alzheimer's disease in genome-wide association studies. Here is the latest research on Alzheimer's disease and MS4A.

Pediculosis pubis

Pediculosis pubis is a disease caused by a parasitic insect known as Pthirus pubis, which infests human pubic hair, as well as other areas with hair including eye lashes. Here is the latest research.

Rh Isoimmunization

Rh isoimmunization is a potentially preventable condition that occasionally is associated with significant perinatal morbidity or mortality. Discover the latest research on Rh Isoimmunization here.

Genetic Screens in iPSC-derived Brain Cells

Genetic screening is a critical tool that can be employed to define and understand gene function and interaction. This feed focuses on genetic screens conducted using induced pluripotent stem cell (iPSC)-derived brain cells. It also follows CRISPR-Cas9 approaches to generating genetic mutants as a means of understanding the effect of genetics on phenotype.

Enzyme Evolution

This feed focuses on molecular models of enzyme evolution and new approaches (such as adaptive laboratory evolution) to metabolic engineering of microorganisms. Here is the latest research.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Pharmacology of Proteinopathies

This feed focuses on the pharmacology of proteinopathies - diseases in which proteins abnormally aggregate (i.e. Alzheimer’s, Parkinson’s, etc.). Discover the latest research in this field with this feed.

Alignment-free Sequence Analysis Tools

Alignment-free sequence analyses have been applied to problems ranging from whole-genome phylogeny to the classification of protein families, identification of horizontally transferred genes, and detection of recombined sequences. Here is the latest research.