Accession Number:

AD0602852

Title:

Ester Synthesis from Inosine, Deoxyinosine, and Ribose-5-Phosphate in Human Erythrocyte chosts,

Descriptive Note:

Final technical rept. for 1 May 63-30 May 64,

Corporate Author:

BOSTON UNIV MASS

Personal Author(s):

Report Date:

1964-07-27

Pagination or Media Count:

13.0

Abstract:

Pathways for the conversion of pentoses to hexoses were studied in ghosts with inosine, deoxyinosine, and ribose-5phosphate as substrates. Inosine and ribose-5-phosphate were qualitatively similar in the synthesis of ketopentosephosphates, triosephosphates, and hexosephosphates. Quantitative differences in turnover rates were found to be dependent on the substrate concentrations of esters incubated. With inosine a hexose to triose ratio of 21 was observed at equilibration, while a ratio of 11 was found with ribose-5phosphate. Hexose synthesis, apparently inhibited at high ribose-5-phosphate concentrations, is explained as a displacement of donor fructose-6-phosphate by acceptor ribose5-phosphate in the bimolecular reaction with the enzyme transaldolase. This acted to stimulate the production of trioses. Phosphoglycerate and lactic acid synthesis also exhibited different kinetic characteristics for both inosine and ribose-5-P. Both phosphoglycerates and lactate increased kinetically with inosine and decreased with ribose-5-P. The data suggest that a pathway from ribose-5-phosphate to phosphoglycerates exists in the erythrocyte. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE