Biochemistry 2280A Chapter Notes - Chapter 11: Rate Limiting, De Novo Synthesis, Emulsion
4 Jul 2020
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11. 1 lipid digestion and absorption: mainly triacylglycerols, minimal in mouth and stomach. Lipid are transported to small intestine: enters duodenum -> emulsification occurs, mixing 2 immiscible liquids, aided by bile. Chylomicrons leave intestine via lacteals and enter via thoracic duct. 11. 2 lipid mobilization: postabsorptive and prolong fasting states favors lipid mobilization, insulin levels, epinephrine or cortisol lipid mobilization from adipocytes. Lipids are mobilized from adipocytes by hormone-sensitive lipase (hsl) Lipids are mobilized from lipoproteins by lipoprotein lipase (lpl) Intermediate transition state between vldl and ldl: triacylglycerol is removed from vldl -> becomes idl, picks up cholesteryl esters from hdl to become ldl. Increase levels of cholesterol can inhibit further synthesis through feedback inhibition. Insulin promote cholesterol synthesis: de novo cholesterol synthesis is dependent on regulation of. Hmg-coa reductase gene expression: specific enzymes, lcat catalyzes formation of cholesteryl esters for transport w/ hdl, cetp catalyzes the transition of idl to ldl by transferring cholesteryl esters from hdl.
