Colipase
Mammalian protein found in humans
Colipase, abbreviated CLPS, is a protein co-enzyme that counteracts the inhibitory effect of intestinal bile acid on the enzymatic activity of pancreatic lipase. It is secreted by the pancreas in an inactive form, procolipase, which is activated by trypsin in the intestinal lumen.
Intestinal bile acids (which aid lipid digestion by facilitating micelle formation) adhere to the surface of emulsified fat droplets, displacing lipase (which is only active at the water-fat interface) from the droplet surface. Colipase acts as a bridging molecule, binding to both lipase and bile acids, thus anchoring lipase onto the droplet surface, preventing its displacement.
In humans, the colipase precursor protein is encoded by the CLPS gene. This precursor protein also contains the satiety signaling hormone enterostatin.
01Protein domain
Colipase is also a family of evolutionarily related proteins.
Colipase is a small protein cofactor needed by pancreatic lipase for efficient dietary lipid hydrolysis. Efficient absorption of dietary fats is dependent on the action of pancreatic triglyceride lipase. Colipase binds to the C-terminal, non-catalytic domain of lipase, thereby stabilising an active conformation and considerably increasing the hydrophobicity of its binding site. Structural studies of the complex and of colipase alone have revealed the functionality of its architecture.
Colipase is a small protein (12K) with five conserved disulphide bonds. Structural analogies have been recognised between a developmental protein (Dickkopf), the pancreatic lipase C-terminal domain, the N-terminal domains of lipoxygenases and the C-terminal domain of alpha-toxin. These non-catalytic domains in the latter enzymes are important for interaction with membrane. It has not been established if these domains are also involved in eventual protein cofactor binding as is the case for pancreatic lipase.
Sources and credits
This article is adapted from the Wikipedia article “Colipase”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.
Images, from Wikimedia Commons:
- Pancreatic lipase–colipase complex with inhibitor 1LPB.png by Fvasconcellos (talk · contribs), Public domain
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