NUTR 3330 Lecture Notes - Lecture 3: Biotinidase Deficiency, Biotin Deficiency, Pyruvate Carboxylase
Document Summary
Biotin: think egg white, rats fed raw egg white developed syndrome of dermatitis, hair loss and neurological abnormalities, called n egg white injury , avidin binds biotin tightly, causing a deficiency leading to symptoms, raw egg diet. Biotin absorption: bound to protein in foods, proteases cleave biocytin from the proteins (biotin pus lysine, biotinidase cleaves biocytin to biotin plus lysine, free biotin is absorbed, where would all this occur, absorption inhibited by avidin. Biotin metabolic function: functions as part of coenzyme for carboxylases, serves as a co2 donor to substrates, co2 fixations reactions, four unique enzymes that depend on biotin, all involved in macronutrient and energy metabolism. Pyruvate carboxylase: glucose metabolism, important step for gluconeogenesis, regenerates oaa for tca cycle, 2. Acetyl coa carboxylase: fatty acid synthesis, 3. Propionyl coa carboxylase: source of energy; entry bro tca, 4. 3-methylcrotonyl coa carboxylase: amino acid metabolism; leucine degradation, se oh for biotin enzyme pathways.
