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


  Amino acid oxidation

  Amino acid excretion

  5′ AMP amino hydrolase activity

  Adenosuccinate lyase activity

  Ribonuclease activity


  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