Potassium (K)is the principal intracellular cation. It is responsible for the maintenance of normal excitability of muscle cells especially heart muscle and nerve cells. It is invovled in the regulation of acid-base balance. The enzyme involved in glycolysis and oxidative phosphorylation are potassium dependent. Potassium is required for the transmission of nerve impulse and adequate intracellular concentration of potassium is necessary for proper biosynthesis of proteins by ribosomes.