where does the pool of free amino acids come from in the body?
body proteins; dietary proteins; synthesized nonessential amino acids.
what takes away from our pool of amino acids in the body?
body proteins -or- synthesis of porphyrins, creatine, neurotransmitters, nucleotides, etc. -or- metabolize them to make energy and CO2 and urea. This would make glucose, glycogen, or ketone bodies, fatty acids, and steroids.
what do we mean by nitrogen balance?
nitrogen intake is about equal to nitrogen loss
what is the general structure of urea
one carbon with oxygen double bound to it and then carbon bound to two amonia
why do we have to make urea?
NH4+ is toxic! and it can't be allowed in the body, so the liver takes it and combines it into a coboxyl and makes Urea
is tyrosine an essential amino acid?
It can be made from phenylalanine
what disease will be cased by an phenylalanine hydroxylase genetic disorder?
PKU -- inability to make tyrosine from phenylalanine
why would phenylalanine and tyrosine be both glucogenic and ketogenic
they can lead to the production of oxaloacatate, and therefore, to the production of glucose, or they can lead to acetoacetate
what happens to the nitrogen when we catabolize or metabolize amino acids
it gets stuck onto things to transport it. specifically it would get stuck on to alpha ketoglutarate, to make glutamate to make glutamine and then sent around the body in the blood.
what does a transamerase do?
It transfers a amino group from an amino acid to an alpha-ketoglutarate to give glutamate
what is the abreviation of Amlamine transamerase
what would elevated levels of ALT mean?
it would indicate tissue damage !
glutaminase would do what reaction?
the reverse of glutamine synthetase: to take glutamine and make glutamate.
what would take glutamate and make glutamine by adding a NH3 group?
glutamine synthetase helps to detoxify ammonia that is not yet converted to urea
The basic flow of nitrogen in amino acid catabolism:
--AA from Muscle; --Make Pyruvate or Oxaloacetate and generate Alpha-ketoglutarte; leads to NH4+ that will be fed into the urea cycle; --Bacteria = NH3 to the liver --Urea cycle in liver takes amonium and gives Urea --Urea as Blood Urea Nitrogen (BUN) goes to Kidney --Kidney excretes as urine
why would glutamine synthetase be most expressed at the end of the hepatic venulle just before the terminal vein? (zone three)
becasue the creation of glutamine is a last ditch effort to trap the toxic NH3 (amonia) that hasn't been processed to urea before it gets into the circulation.
why would glutaminase be most likely expressed in hepatocytes located near the hepatic triage? (zone one)
because glutaminase is releaseing the amonia for the urea cycle.
what would happen to ammonium, glutamine, and BUN (blood urea nitrogen) if difficient in the urea cycle?
ammonium up, glutamine up, and BUN down
what is the general cycle of the urea cycle?
ornithine (an A.A.) in the mitochondria binds with an amonia (make citruline), go to cytosol, gain aspartate, lose fumarate (aspartate w/o amine) produce urea and ornithine again...
where do proteins fit into the overview of catabolic metabolism?
what are the key players in nitrogen acceptance (transport)
Alpha ketoglutarate that accepts an amine to become glutamate (accomplished by a transamerase), then glutamate can accept an amine to become glutamine (accomplished by glutamin synthetase).
what are the key players in nitrogen exchange from proteins to lead into the TCA cycle or into gluconeogenisis
Alanine can become pyruvate (accomplished by a transaminase transfer to glutamate); Aspartate can become Oxaloacetate (accomplished again by making glutamate).
Can be elevated and lead to pyrimidine nucleotides if urea cycle is deficient
what does the presence of AST/ALT in the blood tell us?
cell damage, these are transamerases that are cytosolic ezymes and shouldn't be in blood.
Swap amino groups between metabolites and play key roles in amino acid synthesis and catabolism
what is the fate of protien in the body?
no storage of protien, so break down muscle and take it in food, make new proteins or send the carbons to glycolytic or TCA paths and the nitrogen to urea
who is likely to be in positive nitrogen balance?
growing kids, pregnant women and convalescing adults.
what leads to positive nitrogen balance?
a net increase in body protein stores!
what leads to negative nitrogen balance?
Truama; illness = need for protien that is not being eaten; Just not eating enough protien; lack of an essential amino acid.
disease caused by inadequate intake of both protein and energy -- severe tissue wasting
inadequate intake of protein and adequate energy intake
what could cause Kwashiorkor disease?
infection or other that leads to catabolic state
why a swollen belly with kwashiorkor
edima because the belly can't secrete enough serum protien to maintain osmolarity!
what transaminase can take alanine and make pyruvate?
Alanine Transaminase (ALT); It uses alpha-ketoglutarate and puts the amine group on it to make glutamate
what transaminase can take aspartate and make oxaloacateate?
Aspartate transaminase (AST) using Alpha-ketoglutarate and making glutamate as well