BIOSCI 106 Lecture Notes - Lecture 6: Goitre, Glutamine, Ornithine
6 Sep 2013
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Document Summary
Its major role is as a cofactor in transamination reactions. Pyridoxal phosphate is a derivative of pyridoxine (b6) Present in meat, cereals, fruits and vegetables. Daily requirement 3 micrograms, dietary recommendation 100mg, toxic at levels of >100mg daily. Deficiencies rare, symptoms often neurological, mainly occurs in alcoholic and elderly people. Transported from muscles to liver combined with pyruvate to form alanine. Transported from brain to liver combined with glutamate to form glutamine. Ammonia reconverted in liver and detoxified to form urea. Created by carbomyl phosphate synthase - biotin dependent as the cofactor. Used in the urea cycle with ornithine to produce citulline. Humans are urotelic, we excrete most our nitrogen waste as urea. Urea is non toxic compared to extremely toxic ammonia and it is water soluble. Urea is filtered from the blood by the kidney"s and excreted via the excretory system eg ureter"s --> bladder ---> urethra, also via sweat.
