VPB 112: General Veterinary Biochemistry (1+1)

BUFFER

• A buffer solution is one that resists pH change on the addition of a small quantity of acid or alkali. Such solutions are used in biochemical experiments, where the pH is to be accurately controlled.
• Body fluids must be protected against change in pH. Because most enzymes are pH sensitive.
• During metabolism acids and bases are produced. In the long run, excess acids or base is eliminated via kidney and lungs. In the short run the body is protected against pH change by buffering systems. Acids produced by the body are carbonic acid, sulfuric acid, phosphoric acid, lactic acid, citric acid, ammonium ions Ketone bodies: acetoacetic acid and β-hydroxybutyric acid.
• Bicarbonate buffer is the major extracellular buffer and phosphate buffer is the major intracellular buffer in the body, which protects the body against the pH change.
• A buffer solution consists of a weak acid and its salt, the conjugate base (the proton acceptor). For e.g. acetic acid and sodium acetate or a weak base and its salts (e.g. ammonium hydroxide and ammonium chloride).
• During buffering strong acid or base is replaced by a weaker one, with a consequent reduction in the number of free hydrogen or hydroxyl ion.