Biochemical Effects of Arsenic, Cadmium and Lead

Biochemical Effects of Arsenic

Arsenic commonly occur in insecticides , fungicides and herbicides. Arsenic exerts its toxic action by attacking SH groups of an enzyme, thereby inhibiting action

SH(Enzyme)SH + O2As(O) >> S (Enzyme)S-As-O + 2OH-

The enzymes which generate cellular energy in the citric acid cycle are adversely affected. The inhibitory action is based on inactivation of pyruvate dehydrogenase by complexation with As, were by generation of ATP is prevented.

A more important step is ATP generation is the enzymatic synthesis of 1,3 diphosphoglycerate from glyceraldehyde 3-phosphate . Arsenic interacts by producing 1-arseno-3-phosphoglycerate instead of 1, 3 diphosphoglycerate.



Biochemical Effects of Cadmium

Cadmium occurs in nature in association of zinc minerals. The biochemical effects of cadmium are

a) At high levels cadmium causes kidney problems, aneamia and bone mammrow disorder.
b) The major portion of cadmium ingested our body is trapped in the kidneys and eliminated
c) Small portion is bound most effectively by the body protein, present in the kidney and rest is stored in the body.
d) When the excessive amount cadmium ion are ingested, it replaces zinc ion at the key enzymatic sites, causing metabolic disorder.
e) High level of cadmium ion causes renal dysfunction, hypertension and cancer.



Biochemical Effects of Lead

Lead is a relative abundant of metal in nature occurring in lead minerals.
a) The major biochemical effect of lead is that its interference with heme-synthesis, which lead to hematological damage. Pb inhibit the several of key enzyme involved in the overall process of heme-synthesis whereby the metabolic intermediate accumulate.
b) The overall effect is the disruption of the synthesis of hemoglobin.
c) Pb does not permit the utilization of O2 and glucose for life sustanency energy production.
d) Higher level of Pb causes anaemia.
e) Elevated Pb levels in blood causes kidney dysfunction.
f) Elevated Pb levels in blood causes brain damage.