Nitrogen Metabolism Flashcards
Name the essential amino acids.
Threonine, lycine, histidine, methionine, phenylalanine, leucine, isoleucine, valine, arginine, tryptophan, tyrosine
Which enzyme removes ammonia from circulation?
Glutamate dehydrogenase
What does glutamine synthetase do?
Detoxifies ammonia (Especially in the CNS) for transport to the liver
What does glutaminase do?
Releases ammonia for use in urea cycle (In liver)
What reaction is present in synthesis and degradation of all amino acids?
Transaminase reactions
What are commonly used as donors/acceptors for animo acids?
Glutamate and alpha-ketoglutarate (Aspartate and oxaloacetate can also be used)
What is produced when amino groups are added to ketoacids?
Amino acids
What is the precursor to glutamate and glutamine?
alpha-ketoglutarate
What is the precursor to aspartate and asparagine?
Oxaloacetate
What is the precursor to serine, cysteine, glycine, and proline?
3-phosphoglycerate
What is the precursor to alanine?
Pyruvate
How is excess nitrogen removed from the system?
Urea cycle
Can amino acids form glucose?
Glucogenic amino acids can enter gluconeogenesis to produce glucose
What do ketogenic amino acids become?
Acetyl CoA or ketones
What are some effects of ammonium toxicity?
Neurological disease, ineffective neurotransmission, inhibited TCA cycle (So less ATP), CNS decline (Coma or death)
How can ammonia be transferred from the CNS to the liver?
Glutamate, can cross BBB
What are the three ways ammonia can be removed from the systems of different species?
Ammonotelic: Free ammonia released into environment (Fish)
Uricotelic: Low solubility, no need for water, high crystallization (Birds)
Ureotelic: Urea soluble, water lost along with urea
In which organ does the urea cycle take place?
Liver
Does the urea cycle require energy or produce energy?
Requires ATP
What are the precursors to the urea cycle?
NH4+, COOH-, aspartate
Where does urea go once it is produced?
Kidney for excretion
