Studies on salivary and pancreatic lipases of the pre-ruminant calf.

Abstract

Salivary and pancreatic lipases of the pre-ruminant calf have been studied using ion-exchange chromatography and gel filtration. In addition, pancreatic lipase has been fractionated using concanavalin A-affinity chromatography. The effects of 5,5'-dithiobis(2-nitrobenzoic acid), organic solvents and trypsin on pancreatic lipase have also been investigated. The effects of taurodeoxycholate on the lipolytic activity of the 2 lipases has been compared. Salivary lipase behaved as a single enzyme on ion-exchange chromatography, and gel filtration gave a mol. wt value of 52,000 for the enzyme. Although pancreatic lipase appeared to be a single enzyme on gel filtration, with a mol. wt of almost 80,000, the lipase was shown by ion-exchange and affinity chromatography to consist of at least 2 enzymes of mol. wts 72,000 and 60,000, and did not require colipase for maximum activity in the presence of high concentrations of bile salts. Colipase-dependent lipase, mol. wt about 45,000, and probably amounting to not more than 10% of the total activity, was also present. This was the predominant form only after large losses in total lipolytic activity had occurred, as after treatment with a mixture of ether, ethanol and deoxycholate, or prolonged action of trypsin. When the concentration of taurodeoxycholate was increased from zero to 1 mM in a tributyrin substrate, the lipolytic activities of calf salivary and pancreatic lipases, and pig pancreatic lipase, increased. At a concentration of 4 mM-taurodeoxycholate, calf salivary lipase activity was higher, that of calf pancreatic lipase lower and pig pancreatic lipase activity markedly lower.