lecture 31 - amino acids as fuel molecules Flashcards
What does the deamination of amino acids generate?
A carbon skeleton used for energy capture, and a free amino group (NH4+) that is generally excreted
What enzyme catalyses the deamination of glutamate, by allowing it to release its amino groups to solution?
Glutamate dehydrogenase
What is transamination?
The process of amino acid deamination whereby an amino group is transferred to a keto acid. Catalysed by aminotransferase enzymes
What coenzyme is required for transamination reactions?
Pyridoxal phosphate (PLP)
What is the coenzyme PLP derived from?
Vitamin B6
What is the role of PLP in transamination reactions?
Carries an amino group from an amino acid to a keto acid
What are the 2 forms of PLP, in terms of prescience of an amino group?
Pyridoxal phosphate (no amino group), pyridoxamine phosphate (with amino group)
What are the 2 steps in a transamination reaction?
Amino group is transferred from an amino acid to pyridoxal phosphate (PLP) so it becomes pyridoxamine phosphate, then amino group transferred to the keto acid, converting pyridoxamine phosphate back to PLP
What is the keto acid pair for glutamate?
alpha-ketoglutarate
What is the keto acid pair for aspartate?
oxaloacetate
What is the keto acid pair for alanine?
pyruvate
What is the role of transamination reactions in the liver?
Required to removed excess nitrogen (as NH4+) from the liver and convert it to urea, which can be excreted.
