Biochemical aspects of the visual process. XXVII. Stereospecificity of ocular retinol dehydrogenases and the visual cycle.
Biochim Biophys Acta
; 384(2): 283-92, 1975 Apr 19.
Article
em En
| MEDLINE
| ID: mdl-1125252
ABSTRACT
A comparative study is made of the stereospecificity of two particulate retinol dehydrogenases from bovine eyes and of horse liver alcohol dehydrogenase. The particulate retinol dehydrogenase of outer segments reacts with the all-trans isomers of retinaldehyde and retinol but not with the 11-cis compounds. In contrast, a particulate retinol dehydrogenase present in pigment epithelium reacts preferentially with the 11-cis compounds. Horse liver alcohol dehydrogenase (EC 1.1.1.1.) can convert both isomers, but the all-trans isomers are clearly preferred. Differences with regard to cofactor preference and stability are also noted. The outer segment enzyme clearly functions in the rhodopsin cycle. It is unlikely that the 11-cis retinol dehydrogenase from pigment epithelium is directly involved in providing 11-cis retinaldehyde from rhodopsin regeneration, but it may serve to make available 11-cis retinaldehyde from rhodopdsin, digested in phagocytized rod sacs, for the synthesis of visual pigment by the visual cells.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Células Fotorreceptoras
/
Visão Ocular
/
Oxirredutases do Álcool
Limite:
Animals
Idioma:
En
Revista:
Biochim Biophys Acta
Ano de publicação:
1975
Tipo de documento:
Article