Is C-26 hydroxylation an evolutionarily conserved steroid inactivation mechanism?
Sterols are essential components of virtually all higher eukaryotic organisms, though the exact identity of the dominating sterol varies between species, from the C-27 of cholesterol in vertebrates to the C-28 and C-29 sterols of plants and invertebrates. In addition to their role as structural components of cell membranes these sterols are also converted into a variety of biologically active hormones. This conversion generally involves modifications of the basic structure of the sterol by dealkylation, hydroxylation and/or isomerization. Recent studies have demonstrated that irreversible inactivation of both plant and insect hormones is achieved by a specific C-26 hydroxylation. The concept of sterol deactivation by 26-hydroxylation appears to be an example of an evolutionarily conserved mechanism that has persisted despite the widely varying requirements for sterols in the species where it has been detected.
Meaney
Steve
S
Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Stockholm, Sweden. steve.meaney@labmed.ki.se
D000818:Animals; D005075:Biological Evolution; D006801:Humans; D006888:Hydroxycholesterols / Q000737:chemistry; D006900:Hydroxylation; D008968:Molecular Conformation; D013256:Steroids / Q000737:chemistry / Q000378:metabolism*
D006888:Hydroxycholesterols; D013256:Steroids; C007042:cholest-5-ene-3 beta,26-diol; C007997:25-hydroxycholesterol