BIOC 311 Lecture Notes - Lecture 29: Fumarase, Cytosol, Hyperammonemia
18 Jun 2016
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Lecture 29: urea cycle samedi 14 novembre 2015. Transamination: first plp forms covalently link with enzyme (internal aldimine). Secondly, formation of an external aldimine intermediate (replaced lysine residue). Then, formation of carbanion intermediate (plp has rigid planar geometry enhanced by pyridine and chelate rings, electron sink where reaction is catalyzed). Lastly, we have formation of pmp and alpha-keto acid. Reversible reaction: in phase i, you form alpha keto acid and pmp. In phase ii to happen, this first product has to leave the enzyme (alpha keto acid). Enzyme takes second alpha keto-acid and perform reverse reaction and form second amino acid. Most transaminase prefer a-kga as keto-acid substrate giving off glutamate => funnelling. (note that there is two substrates and two products in phases i and ii) Glucose-alanine cycle: transportation of ammonium in body, transports from muscle to liver (where n free amino group is detoxified and converted to urea).
