Zinc metalloenzymes catalyze approximately 50 important biochemical reactions. Many of these enzymes have been isolated from more than one species, resulting in identification of over 200 catalytically active zinc metalloproteins. Carbonic anhydrase, alcohol dehydrogenase, alkaline phosphatase and steroid hormone receptors are examples.
The functions of zinc in metalloenzymes are catalytic structural, regulatory and noncatalytics. Examples of enzymes in which zinc plays a catalytics role include carbonic ahnydrase, carboxypeptidas, thermolysin, and aldolases.
Excessive intake can cause adverse effects in humans and animals. In human, the effects of acute zinc toxicity are gastrointestinal disturbances giving rose to abdominal pain, nausea and vomiting. Chronic zinc toxicity is associated with changes in copper balance leading to symptoms of copper deficiency.
Zinc deficiency is an important part of protein-energy malnutrition and may limit weight gain during refeeding unless adequate amounts are provided.
The average daily dietary intake of zinc is around 150 umol. It is present in all protein rich foods.
Biochemistry of zinc
