Lecture 18 Amino Acid Metabolism Flashcards
(49 cards)
What are the three step of nitrogen metabolism
Assimilation (from ammonia)
redistribution (transamination)
Disposal (urea cycle)
where does nitrogen fixation begin
in the root nodules using bacteria of macrorrhiza (turn N2 into ammonia (NH3)
Why don’t we fix nitrogen?
bc its way to energy intensive
can some organisme (not us) oxidize ammonia to get energy
yes some plants and bacteria and fungi
what is glutamate generated from
alpha ketoglutarate
what amino acid is best at laundering nitrogen
glutamate
what are the general two steps of amino acid degradation
transamination
glutamate dehydrogenase
why do we want to take an amino group off of a AA
so its carbon skeleton can enter central metabolism
what is the first step of amino acid degradation and how does it work
pathway?
name of enzyme?
Transamination done by the transaminase enzyme
alpha ketoglutarate + alpha amino acid (starting A acid) —> Glutamate + alpha keto acid
amino group gets ripped off AA and put on A Ketoglutarate which turns it into Glutamate and you have a nakes Alpha keto acid left over with no amino group
are there diffrent transaminases for each AA
yes
is transamination reactions reversible
yes
what is the relationship between Glutamate and Alpha ketoglutarate
glutamate is just A ketoglutarate with an amino group on it
what is the second step of amino acid degradation? balance sheet? what do you make
Glutamate dehydrogenase is when you take glutamate and reduce NAD+ to NADH and also get ammonia as a byproduct
Glutamate + H2O + NAD(P)+ —-> Alpha Ketoglutarate + 2H+ + NAD(P)H + N3
is glutamate dehydrogenase reaction reversible
yes
what is the purpose of dehydrating glutamate after transamination
to regenerate A Ketoglutarate
where is glutamate dehydrogenase located
in the mitochondrial matrix
how is ammonia removed form the body
urea cycle
draw urea
look it up
difference between synthase vs synthETase
synthETase uses Ntp to make something and synthase do not
characteristics of the enzyme that converts glutamine to glutamate
is a synthETase, and is a multimer so its cooperative (IE regulated) and is reversible
What is the cofactor for transamination reactions
PLP (Pyridoxal Phosphate)
what can PLP do
it can form a covalent nitrogen bond to an AA and be a schiff base (electron sink in order to do rip off amino groups and shove them on other keto acids to make new amino acids)
what can Pyridoxal Phosphate
it can form a covalent nitrogen bond to an AA and be a schiff base (electron sink in order to do rip off amino groups and shove them on other keto acids to make new amino acids)
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what are the two ways in which carbon skeleton of AA can enter central metabolism
glucogenic
ketogenic
