L7 - Biosynthesis of AA and Molecules

alanine synthesized

pyruvate + glutamate + alaATransferase > alanine + aKG

asparagine synthesized

by amidation of aspartate

asp + ATP + glutamine + asp synthetase > AMP + PPi + glutamate + asparagine

cat. by asp synthetase, needs ATP

aspartate synthesized

OA + transaminase + glutamate > aspartate + aKG

asparagine + H2O + asparaginase > aspartic acid + NH3 (deamidation)

asparagine synthetase

NH3 donated by glutamine

aprotic tunnel, other side has b-aspartyl-AMP, which NH3 attacks

glutamate synthesis review

transamination:

• aKG + AAx + transaminase > glutamate + aKAx

red amination:

• aKG + NH3 + NADPH + GDH > glutamate + NADP+

hydrolysis

• glutamine + glutaminase + H2O > glutamate + NH3

conditionally essential amino acids

arginine = synthesized in urea cycle

creatine = synthesized from arginine indirectly

creatinine = waste product and indicator of renal function

arginine is synthesized mostly in

urea cycle

creatine is mostly synthesized from ____ or phosphorylated by ____ to store energy as ____

arginine indirectly; creatine kinase; phosphocreatine

creatine is made in the ____ from the ____

liver pancreas kidneys, transamination of

arginine, glycine, methionine

creatinine

waste product and indicator of renal function;

filters stuff from blood in kidneys

phosphocreatine

high energy phosphate bonds for ATP shortage

in muscles, phosphorylates ADP > ATP

creatine kinase

serum levels, isoforms, can be used to diagnose acute heart attacks

SAM in creatine formation

arg + glyc > ornithine + guanidoacetate

guanidinoacetate + SAMeth > creatine + SAH

cysteine and selenocysteine

proteinogenic, incorporated into selenoproteins

UGA = stop codon

derivative of serine, uses PLP

UGA stop codon

if not enough selenocysteine, we insert selenocysteine instead of stopping

tyrosine

phenylalanine hydroxylase

conditionally essential, synthesized from phenylalanine

precursor of neurotransmitters

phenylalanine hydroxylase

cat hydroxylation of C4 phenylalanine

BH4 dependent

PKU

genetic disorder, autosomal recessive

elevated phenylalanine or phenylpyruvate

damages in neuro, head size, etc.

treated with diet and supplements reducing phenylalanine and increasing tyrosine

specialized n molecules

thyroxine

thyroxine

controls metabolic rate, O2, ATP, fat, myosin, etc.

T4 = tetraiodothryonine = thyroxine = precursor

T3 = trioiodothrynonine = active

enzyme is a selenoprotein

SAM/Ado-Met

s-adenosylmethionine; abundant methylating agent

methionine + ATP, vitamin B12 indirectly affect levels

synthesis of homocysteine, creatine, and epinephrine

glutathione GSH

cellular reducing agent, made from glutamate, cysteine, and glycine

glutathione peroxidase GPX

selenoproteins to help scavenge free radicals

nitric oxide

messenger in Neurotransmission, blood clotting, BP

made from arginine + NO2Synthase + NADPH > citrulline + NO2

amino acid neurotransmitters

glutamate

aspartate

d-serine

glycine

glutamate

main excitatory neurotransmitter; stored in synaptic vesicles

CNS, memory, cognition, mood;

may bind NMDA receptor

aspartate

excitatory neurotransmitter, will bind NMDA

d-serine

co-agonist of NMDA type glutamate receptors

glycine

inhib neurotransmitter in spinal cord, brainstem, retina

epinephrine

adrenaline; hormone and neurotransmitter

binds to B adrenergic receptor

norepinephrine

more effect on blood vessels

binds to a receptors 1 and 2, B1, not B2

made from tyrosine

catecholamines

stress response: brain, nerve, adrenal

dopamine, norepinephrine, epinephrine

comes from tyrosine

GABA

inhibitor neuro, reduces excitability

B6 dependent

comes from glutamate

serotonin

from tryptophan,

mood, sleep, digestion

BH4 dependent

histamine

vasodilator, decarboxylation of histidine

cimetidine

tagamet;

analog antagonist of histamine

dopamine

made in brain, adrenal glands

memory, mood, sleep, learning

parkinsons, ADHD, restless leg