How do bile salts affect lipase activity?

Question

**BACKGROUND**: It is well known that bile salts are needed for emulsification of fats. It is then said that this increases the surface area for activity of pancreatic lipase, implying that bile salts make pancreatic lipase more effective. But it is also said that pancreatic lipase do need a colipase to overcome the **_inhibitory effect from bile salts_**.----**QUESTION**: So what does bile salts actually do? Do they increase or decrease lipase activity? How does colipase overcome it?---**MY ATTEMPT**: After some research , I found that bile salts above critical micelle concentration have inhibitory effect, but could not still comprehend how does the colipase makes lipase more efficient. Also if greater concentration is inhibitory then why does our body just secrete it in sufficient amounts? Isn't it be more efficient than to make a whole protein(colipase)?

Answer 1

Human pancreatic lipase is primarily regulated by bile salts, colipase, and Ca²⁺ (These 3 are important). When all 3 are present, bile salts are responsible for activation. This is generally the most efficient pathway. When only bile salts and colipase are present, the reaction is inhibited. Likewise, when only bile salts and Ca^2+, the reaction is also inhibited. Having all 3 is advantageous, while having only 2 is inhibitory.