VPB 121: Veterinary Physiology - II (2+1)

GASTRIC ENZYMES

Pepsin

• Proteolytic enzyme, involved in hydrolysis of proteins into polypeptides
• Synthesized as “Pepsinogen” (inactive form of pepsin)
• Pepsinogen is activated by HCl 
• Optimum pH of 1.5 – 3 is required for pepsin activity

Rennin(Chymosin, Rennet)

• It is a milk coagulating enzyme, present in young animals(Calf, Lamb, piglet etc.,)
• Secreted as prorennin (inactive form of rennin)
• Prorennin is activated by HCl
• Rennin reacts with casein (Milk protein)  in the presence of calcium ion forms calcium paracaseinate to delay the passage of milk through stomach for prolonged action of pepsin on casein 

Gastric lipase

• Acts on emulsified fat
• Hydrolysis fat in to fatty acids and glycerol
• Require the optimum pH of 5.5 – 7.5
• Its concentration in carnivores is low
• Absent in birds and ruminants.