383 — Trace metal requirements in total parenteral nutrition: II. Potentiometric study of the metal—ion equilibria in the zinc—histidine, zinc—glycine, zinc—cysteine—histidine, zinc—glycine—histidine and zinc—clycine—cysteine systems under physiological conditions

Abstract

In the order to allow a better simulation of the distribution of the zinc complexes that pertain to a nutritive mixture used in total parenteral nutrition (TPN), the equilibrium constants for the ternary systems zinc—cystein—histidine, zinc—glycine—histidine and zinc—glycine—cysteine, and the binary systems zinc—histidine and zinc—glycine have been investigated — or reinvestigated when already studied — under experimental conditions corresponding to blood plasma (37°C, 0.15 M NaClO 4). The incidence of the results on the previously predicted dose of zinc for TPN is briefly discussed.