NUSCTX 103 Lecture Notes - Lecture 21: Vitamin, Naphthoquinone, Gut Flora
3 Dec 2020
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Vitamin k1: phylloquinone: primary dietary source of vitamin k, leafy plant species are richest source, also present in vegetable oils, liver, cheese and eggs are poor sources, vitamin k in nutrient supplements. The largest organ that stores vitamin k, can recycle vitamin k: does not apply to other fat-soluble vitamins. A vitamin k-dependent gamma carboxylase: the main biochemical function of vitamin k is cofactor in a gamma-carboxylation reaction, converts glu to gamma-carboxyglutamate (gla, gla residues are good ca2+ chelators, bind calcium through electrostatic reactions. Carboxylation occurs in the er liver er: proteins that need to be exported outside of the cell biosynthesized in the lumen er. Outside of the cell in some way because of its environment: rough er, decorated with numerous ribosomes. Recognized by enzyme (vitamin k dependent, catalyzing the reaction). Only a certain number of glutamate at the end n-terminus will be gamma carboxylated.
