BIOC 406 Lecture Notes - Lecture 7: Glutamate Dehydrogenase, Glycogen Phosphorylase, Mitochondrial Matrix
Document Summary
We don"t have a storage form of nitrogen, but we want to use the amino acid"s carbon skeleton for other purposes because we can store that. Amino acids are great precursors for gluconeogenic and ketone body synthesis. If ammonia builds up, it is toxic, so you have to convert it into a non toxic form that you can get rid of = the urea cycle. There are four central amino acids in a. a. metabolism: alanine, aspartate, glutamine, and glutamate. They are easily converted to glycolytic and tca cycle intermediates. Glutamine synthase takes glutamate and uses atp to make a high energy intermediate. It makes the carbon very susceptible to nucleophilic attack. Ammonia can come in and drive off the phosphate to give glutamine. Carbamoyl-phosphate synthetase -i is a liver enzyme in the mitochondrial matrix that turns out to be the key enzyme in the urea cycle.
