Ascorbic acid as a factor controlling "in vivo" its biosynthetic pathway.
Boll Soc Ital Biol Sper
; 65(10): 959-65, 1989 Oct.
Article
em En
| MEDLINE
| ID: mdl-2624714
ABSTRACT
The capacity of ascorbic acid biosynthesis in potato tuber tissue is closely correlated with the ascorbic acid content of the cells the lower the endogenous content of ascorbic acid, the greater its biosynthesis. At the highest level of ascorbic acid found in the cells, the biosynthetic capacity is virtually zero. In these conditions, adding glucose (the first precursor of ascorbic acid) has no effect whatsoever, whereas adding galactono-gamma-lactone (the last precursor) induces a high rate of ascorbic acid synthesis. It is suggested that AA biosynthesis is subject to a regulatory mechanism "in vivo" which controls an initial step in the biosynthetic pathway. The last step in this pathway, catalyzed by galactone oxidase, is never blocked and, moreover, its activity is greater than that of the preceding steps.
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Base de dados:
MEDLINE
Assunto principal:
Ácido Ascórbico
/
Solanum tuberosum
Idioma:
En
Revista:
Boll Soc Ital Biol Sper
Ano de publicação:
1989
Tipo de documento:
Article