Carbon and hydrogen metabolism of xylitol and various sugars in human erythrocytes.
1) Erythrocytes are able to metabolize D-ribose, D-xylitol, D-xylulose, D-fructose and D-glucose; the rates of metabolism increase in that order from 2430 to 26200 ng atom C/ml packed cells per 120 min of incubation. 2) The utilization of the carbon of these substrates and its recovery in the products were found to be in balance, when the change in the 2,3-bisphosphoglycerate concentration was taken into account. 3) The metabolic rates strongly affected the 2,3-bisphosphoglycerate level. Without addition of substrate the decomposition rate of this intermediate was found to be 1030 nmol/ml packed cells per 120 min. 4) The net decrease of the 2,3-bisphosphoglycerate concentration and the conversion of this compound into lactate provides a NAD regeneration system which enables the red blood cells to utilize xylitol. 5) The rate of carbon metabolism via the pentose phosphate cycle is determined by the NADPH requirement of the erythrocytes which was found to be 160 nmol/ml packed cells per 120 min under the experimental conditions employed.
D002244:Carbon / Q000097:blood*; D002245:Carbon Dioxide / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism*; D005994:Glycerophosphates / Q000378:metabolism; D006801:Humans; D006859:Hydrogen / Q000097:blood*; D007773:Lactates / Q000378:metabolism; D009243:NAD / Q000378:metabolism; D011773:Pyruvates / Q000378:metabolism; D014993:Xylitol / Q000097:blood*
D005994:Glycerophosphates; D007773:Lactates; D011773:Pyruvates; D009243:NAD; D002245:Carbon Dioxide; D002244:Carbon; D006859:Hydrogen; D014993:Xylitol