ABSTRACT
The biological role of zinc is invariably associated with protein synthesis and metabolism (see Table 23). While this is unquestionably a dominant role for zinc, it should be borne in mind that zinc has significant interactions with other major and minor nutrient classes as well, particularly lipids. Furthermore, it has as yet been difficult to definitively relate the effects of experimental zinc deficiency to specific alterations in protein synthesis. Zinc is also a structural and catalytically active component of the enzymes involved in nucleoprotein synthesis. Whereas a functional deficiency in protein synthesis caused by zinc deficiency has not been demonstrated, a failure to adequately synthesize nucleoproteins and to complete the processes of cell replication is a recognized effect of zinc deficiency. Hence, zinc deficiency more significantly affects cell division, which is a function of nucleoprotein synthesis than cell growth and enlargement, which is a function of protein synthesis. Interaction of Zinc with Proteins
Chelation by sulfhydryl-containing amino acids (cysteine)
Chelation by nitrogen-containing amino acids (histidine)
Induces metallothionein
Increases hemoglobin affinity for oxygen
Stabilizes and binds tubulin
Facilitates DNA denaturation/renaturation
Stimulates protein phosphorylation
Zinc-deficiency causes
Increased
Amino acid oxidation
Amino acid excretion
5′ AMP amino hydrolase activity
Adenosuccinate lyase activity
Ribonuclease activity
Decreased
Incorporation of cysteine and methionine into proteins
Collagen cross-linking
Total collagen (tissue-specific)
DNA and RNA polymerase (tissue-specific)
Thymidine kinase
Methionine and thymidine incorporation into DNA
