Integration of Other Metabolic Pathways Flashcards
How is nitrogen excreted in fish?
NH4+
How is nitrogen excreted in birds?
Uric acid
How is nitrogen excreted in mammals?
Urea
What occurs in step 1 of nitrogen excretion?
NH4+ is produced by amino acids trasnferring their N to glutamate
Which enzymes catalyse the transfer of an amino group from an amino acid to a keto acid?
Aminotransferases
What reaction occurs with most amino acids in the 1st step of nitrogen excretion?
Amino acid + α-ketoglutarate ⇌ keto acid + glutamate
Which enzyme deaminates glutamate?
Glutamate dehydrogenase
What is unusual about glutamate dehydrogenase?
It is not specific about whether it uses NAD or NADP
Where does the action of glutamate dehydrogenase occur?
The mitochondrial matrix
Why does glutamate dehydrogenase act in the mitochondrial matrix?
To keep toxic NH4+ out of the cytosol
What is thethe equation for the reaction glutamate dehydrogenase undergo?
Glutamate + NAD+ (NADP+) + H2O⇌ α-ketoglutarate + NADH/P + H+ + NH4+
