Health & Environmental Research Online (HERO)


Print Feedback Export to File
8408523 
Journal Article 
Enzymic synthesis of l-ascorbic acid from synthetic and biological d-glucurono-1,4-lactone conjugates 
Dutta Gupta, S; Sen Gupta, C; Ray Chaudhuri, C; Chatterjee, IB 
1970 
Yes 
Analytical Biochemistry
ISSN: 0003-2697
EISSN: 1096-0309 
38 
1 
46-55 
English 
d-Glucofuranosiduronolactone conjugates, namely, semicarbazone, oxime, cyanohydrin, and thioacetal of d-glucurono-1,4-lactone, were converted to l-ascorbic acid by an enzyme system present in rat, goat, or rabbit liver microsomes. Guinea pig liver microsomes were ineffective. Neither methyl-d-glucofuranosiduronolactone nor any glucopyranosiduronic acid conjugates examined were converted into l-ascorbic acid. Methods of preparation and properties of d-glucurono-1,4-lactone semicarbazone and d-glucurono-1,4-lactone oxime have been described and a tentative mechanism of enzymic reduction of the conjugates into l-gulono-1,4-lactone has been suggested. A conjugate of d-glucurono-1,4-lactone and imidazole, which is a substrate for the microsomal enzyme leading to synthesis of l-ascorbic acid, has been identified in the urine of rat treated with chloretone, barbital, and 1,2-benzanthracene. It has been indicated that the enhanced synthesis of l-ascorbic acid after administration of various drugs and toxic chemical compounds is due to the induced formation of this endogenous substrate. © 1970.