Role of Coordination and Chelation in Utilization of Nutritionally Essential Trace Elements.
Final rept. 1 Sep 69-31 Oct 70,
MARYLAND UNIV COLLEGE PARK DEPT OF CHEMISTRY
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Competition for metal ions by various substances in the biological system will establish the chemical composition of the metal compounds and consequently the availability of the metals. Since reactions incorporating metals into polymeric non-diffusible molecules would make the metals unavailable, it is of interest to determine which biological ligands can prevent or retard such processes, which can be done by sequential dialysis. In previous studies, many biological substances were shown by this method to be effective ligands for CrIII IN THE PRESENT INVESTIGATION4 HISTIDINE, GLUCONATE, SACCHARATE AND THREONINE WERE FOUND TO HAVE GREAT COORDINATING TENDENCY. The PO sub 4 to the third power ion itself used as a buffer is quite effective. Sequential dialysis is as applicable to FeIII as to CrIII and probably to other essential metal ions effective ligands for FeIII are ADP, pyrophosphate, triphosphate, fructose-1, 6-diphosphate, beta-glycerophosphate, citrate, isocitrate, saccharate, mesoxalate and oxalacetate. Some comparison of membranes was accomplished. Membrane filters are satisfactory but expensive and it is impossible to decontaminate them of radioactivity sufficiently to permit their re-use. Regenerated cellulose is by far the most satisfactory membrane but some lack of uniformity was observed. Author