Colipase

Catalase (bovine liver)[17] a-Chymotrypsin1183 Colipase (pancreatic)[19] Collagenase[20]... 

Various pancreatic enzymes hydrolyze lipids, including lipase with its auxiliary protein colipase (see p. 270), phospholipase A2, and sterol esterase. Bile salts activate the lipidcleaving enzymes through micelle formation (see below). 

Lowe, M.E. 1999. Assays for pancreatic triglyceride lipase and colipase. In Methods in Molecular Biology, Vol. 109 Lipase and Phospholipase Protocols (M.H. Doolittle and K. Reue, eds.) pp. 59-70. Humana Press, Totowa, N.J. 

For an example of neutron diffraction applied to a crystallographic problem, see D. Pignol, J. Hermoso, B. Kerfelec, I. Crenon, C. Chapus, and J. C. Fontecilla-Camps, The lipase/colipase complex is activated by a micelle Neutron crystallographic evidence, Chem. Phys. Lipids 93, 123-129, 1998. 

Patton, J.S. and Carey, M.C. 1981. Inhibition of human pancreatic lipase-colipase activity by mixed bile salt-phospholipid micelles. Am. J. Physiol. 241, G328-G336. 

Young, S.C. and Hui, D.Y. 1999. Pancreatic lipase/colipase-mediated triacylglycerol hydrolysis is required for cholesterol transport from lipid emulsions to intestinal cells. Biochem. J. 339,... 

As illustrated in Figure 2, human pancreatic lipase consists of two domains. The larger N-terminal domain, a mixed 0E,P-stmcture, comprises residues 1-335 and contains the catalytic triad and a calcium-banding site. The smaller C-terminal domain is formed by two layers of antiparallel -strands and presents a binding site for colipase. 

Figure 4, where the curve is the result of opposite effects of colipase and bile salts. Maximum activities am reached in the range of 5-13 mM bile salts, a concentration aiso present in the duodenum during fat digestion, in me FI method for pancreatin lipase, about 10 mM FIP controlled sodium taurocholate is used. 

It is dear that the interconnection between the activities of the different lipolytic enzymes, where the first enzyme modifies the physicochemical state of the lipid substrate in such a way that it becomes available to another enzyme, is not only of prime importance for lipid digestion, but also results in a broad synergism between gastric lipase, colipase, pancreatic lipase, phospholipase As. calcium, caiboxylester Lipase, bite salts, and substrate interraecK tes [55,62-64]. 

Q. Chen, B. Stemby, B. Akesson, and A. Nilsson. Effects of human poncreftlc lipase-colipase and carboxyl ester lipase on eicosapentamoic and aiachidontc acid ester bonds of triacylglycerols rich in fish oil fatty adds. Biochim. Bbphys. Acta 7044 111(1990). 

Bemback, L fiiacabcig, and G. Hcmcli. The compieie digestion of human milk triacylglyccxol In vitro requires gastric lipase, pancreatic colipase-depcndent lipase and bile salt-stimulated lipase. J. Clio. Invest. Jf5 1221 (1990). 

The last point has been demonstrated in several contexts, most notably in protein kinase C [109, 110] and phospholipases [111-113], in coupling of G-proteins to their receptors [114], and in the activation of pancreatic lipase by colipase [115]. 

The pancreas produces several lipases, the classical lipase (pancreatic lipase, PL) and the pancreatic lipase-related proteins 1 (PLRP1) and 2 (PLRP2). In addition there is a protein named colipase, which is necessary for the activity of PL. PLRP1 seems to be devoid of lipase activity, while PLRP2... 

Dietary triglycerides are hydrolyzed in the small intestine by pancreatic lipase. This enzyme action is associated with a cofactor, colipase, also a pancreatic protein, molecular weight (MW) 12,000, which helps to anchor lipase to the fat droplets. Without colipase, lipase is rapidly denatured. Colipase is apparently secreted by the pancreas as a zymogen and is activated to its active form in the small intestine by trypsin. Pancreatic lipase appears in the circulation in large amounts during acute pancreatitis. 

Bernback, S., Blackberg, L., Hernell, O. 1989. The complete digestion of human milk triacyl-glycerol in vitro requires gastric lipase, pancreatic colipase-dependent lipase, and bile salt-stimulated lipase.. / Clin. Invest. 85, 1221-1226. 

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