9b Flashcards
whats transamination and what cofactor do we need to do this
when we transfer an amino group to a keto acid to form new aa
we need PLP to do this
when theres an amino group on the cofactor what do we call it
we call it E-PMP
what does E-PMP do and what does it react with
it reacts with pyruvate by using its amine groups lone pair to attack the bottom carbonyl of pyruvate
this forms an imine!!
when E-PMP reacts with pyruvate,, what happens after imine formation
a H is removed and the e- are conjugated onto the e- sink to neutralise the N(+)
when E-PMP reacts with pyruvate and the e- are conjugated onto the e- sink to neutralise N,, what happens after
the neutralised N then usues its lone pair to conjugate back up and hydrogenate the imine so u get another imine but then u also get a chiral carbon!!!
and u need to make sure that the N is wedged bc the imine attacks the H from the bottom face,, aka the bottom face of the imine is protonated.
this is important in order to get the correct amino acid
okay so one E-PMP reacts with pyruvate and hydrogenates the imine to form another imine and a chiral centre, what happens
water then hydrolyses the imine and u get a carbonyl againnnn
aka PLP is regenerated as now theres a carbonyl at the top
u also form a new amino acid
in this case its alanine
E-PMP and pyruvate give u what amino acid
alanine
where do we get N frommm aka whats our main amino acid donor
glutamate!!!!
what is glutamate once u lose the NH2
its alpha ketoglutarate
once u lose the NH2
when the NH2 of glutamate,, aka our amino donor,, is removed,, where does it go
it goes onto E-PLP,, the carbonyl one,, to form PMP,, the NH2 one!!
this is how w transer nitrogen to diff things!!
u then react the E-PMP with pyruvate and the N gets moved onto the pyruvate to form alanine!!!!
what stereognic centre does alanine have
it has an S stereogenic centre
whats the overall reaction for alanine synthesis
- glutamate (N donor) + pyruvate
gives alanine + alpha ketoglutarate
biosynthesis of aspartate,, what do we need
oxaloacetate ( -OOC- CH2 - C=O - COO- )
and aminotransferase
to give aspartate
-OOC- CH2 - CH2- C,H,NH3+ - COO-
biosynthesis of glutamate,, what do we need and why is glutamate important
glutamate is where we get our NH2 from!!!
its synthasised in microorganisms but not in vertebrates
we need alpha ketoglutarate + amino transferase to ge glutamate.
what does alpha keto glutarate look like
- OOC CH2. CH2. C=O COO-
what does glutamate look like
-COO. ch2. ch2. C, H , NH3+ COO-
amino acids are made from intermediates of what reaction
theyre made from intermediates from glycolysis, pentose phosphate pathway and the citric acid cycle
valine and leucie are similar in what way
the way theyre made
u make valine and if u turn right u make leucine
what cofactor do leucine and valine synthesis both need and what does it do
they need TPP
thiamine pyrophosphate!!!
this allows us to make a (-) by reversing the charges on a carbonyl so we can attack other molecules // forms a double bond that we can use to attack other molecules
it also needs amino transferase to catalyse the final steps of the reaction and add the NH2 in!!!
whats our amino donor
glutamate
in the formation of valine,, TPP and pyruvate react to form what
they react to form hydroxy ethyl - TPP
whats the imporatnce of TPP
it stabilises the carbonation,, which would normally be rlly unstable bc its tertiary but here its stable
what does hydroxy ethyl TPP look like
H3C - C (-) OH - TPP
in the formastion of valine,, what does the hydroxy ethyl TPP attack
it attacks another pyruvate!!!
the carbanion attacks the carbonyl of the pyruvate and the carbonyl is then protonated to form OH
