FNH 351 Lecture Notes - Lecture 4: Fatty Acid Desaturase, Vitamin B6, Glycogen Phosphorylase

• School: UBC
• Department: Food, Nutrition and Health
• Course: FNH 351
• Professor: Yvonne Lamers

Document Summary

Plp in schiff base linkage to the amino group of an enzyme side chain. Plp blocks albumin gene expression by binding to transcription factors. Formation of plp is atp and fmn dependent. Some metabolic trapping, then phosphorylated (trapped as plp/pnp/pmp) Conjugated b6 (pn beta-glucoside) need to be hydrolyzed by mucosal glucosidase. Pn/pl/pm diffuse into jejunum -> hepatic portal vein -> liver via diffusion. Pl + plp -> blood -> extrahepatic tissues. Blood (75-90%): mainly as plp (and pl), bound to albumin. Rbc take up and convert pl/pn/pm -> plp (binds to hemoglobin) 75-80% in muscle (plp bound to glycogen phosphorylase) Excrete in form of pn and 5pa, lower excretion of 4pa. Coenzyme in digestion of b6, dephosphorylate pmp/pnp/plp for absorption. Fmn as coenzyme for oxidase, convert pnp/pmp -> plp. High dose b6 supplement needed (100-500mg) to improve symptoms, monitor for signs of toxicity.