BMCB 658 Lecture Notes - Lecture 20: Phylloquinone, Leukotriene, Thromboxane
19 Aug 2016
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Document Summary
Vitamin: organic compound essential for the proper functioning of the body: obtained from dietary sources; human body cannot synthesize it. Coenzymes: vitamin derivatives required for certain enzymes. Isoprene: building block for variety of molecules, two or more isoprene molecules = terpenes, monoterpene = 2 isoprenes, sesquiterpene = 3 isoprenes, diterpene = 4 isoprenes. Enzyme-catalyzed cleaved of -carotene followed by reduction gives two molecules of vitamin a. Retinol acts as prosthetic group for the protein opsin. Alcohol group (retinol) is enzymatically oxidized to an aldehyde to form 11-transretinal. 11-cis-retinal links to opsin by lysine residue. Rod cells: low-light vision, discs rich in opsin, opsin + 11-cis retinal = rhodopsin. Vitamin d: involved in regulation of calcium metabolism. Bone matrix is mostly calcium phosphate: d3 (cholecalciferol) is the most abundant form, not required from diet because it comes from uv light, low [d3] can lead to bone malformation.
