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44 Cards in this Set
- Front
- Back
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AA catabolism produces what that is toxic?
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Ammonia
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What is positive nitrogen balance?
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When you take in more nitrogen than excreted...children and pregenant women are commonly in positive nitrogen metabolism
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What is negative nitrogen balance?
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Taking in less amino acids than you are excreting. Happens in malnutrition or catabolic stress (i.e. infection)
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What is a hypercatabolic state?
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A state of increased fuel usage. Negative nitrogen balance. Seen in trauam, injury and infection.
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Which hormone is usually elevated in a hypercatobolic state?
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Coritsol
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List the essential amino acids:
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Phenylalanine
Valine Tryptophan Theronine Isolucine Methionine Histadine Arginine Leucine Lysine |
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Where do we get out essenital amino acids from?
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Dietary and protien turnover (breakdown)
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Tyrosine is made from?
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Phenylalanine
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Cystine synthesis requires?
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Methionie
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How are amino acids used in a fed state?
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AA's will be used to make proteins the extras are broken down to make energy or fat
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How are amino acids used in a fasted state?
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Skeletal muscle protein will be broken down to use in gluconeogenesis or energy. Some will be used to synthesize needed proteins.
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What is a glucogenic amino acid?
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Degraded to pyruvate or TCA cycle intermediates
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What is a ketogenic amino acid?
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Degraded to acetyl CoA or acetoacetate
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How does insulin effect amino acid metabolism?
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promotes AA uptake and protein synthesis
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How does cortisol effect amino acid metabolism?
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promotes gluconeogensis thus AA will be used as precursurs
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How does glucagon effect AA metabolism?
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Stimulate AA uptake by liver
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What is the role of skeletal muscle in AA metabolism in fasted state?
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Skeletal muscle proteins will break down for AA to use as energy
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What is deamination?
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Removing the NH3 group off an amino acid resulting in free ammonia group. Glutamate DH is an example of a deamination enzyme.
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What is transamination?
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Transamination is the transfer of NH3 group to something else. Example: Alpha-ketoglutarate to glutamate
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What are the two ways of removing nitrogen from AA?
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Transaminiation and deamination
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What is the importance of alpha-ketoglutarate?
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Important in tranaminating AA to glutamate. alpha-keto is produced from transamination.
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Aminotransferases/transaminases require what as a cofactor?
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PLP (Pyridoxal phosphate) Vitamin B6
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Why is it important that transaminanes are reversible?
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So alpha-ketoglutarate can be regenerated
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What is the product of ALT?
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Pyruvate ---ALT ---> Alanine
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What is the product of AST?
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OAA ---AST ---> Aspartate
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What is the importance of AST and ALT in diagnosing liver disease?
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Elevated serum levels of AST and ALT mean liver damage
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Why are glutamate, glutamine, and alanine important?
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They transport NH3 to liver so they can be excreted in the urea cycle.
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Where does the urea cycle occur?
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Liver
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Which enzymes are involved with urea cycle?
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CPS1 and OTC
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Where do the first two steps of the urea cycle occur in the cell?
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Mitochondria
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Which amino acid is produce by the urea cycle?
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Arginine
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Urea formation requires energy and is irreversible, true or false?
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True
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What is the rate imiting step in the urea cycle?
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CPS1 is the rate limiting step
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How is the urea cycle regulated?
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Mostly substrate avalibiility (feed forward) regulated
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What is important about NAG?
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CPS1 is stimulated by NAG which is produced from acetyl CoA + glutamate
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Where does urea go after it is synthesized?
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Into the blood stream to be excreted by kidneys
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What is BUN?
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Blood urea nitrogen
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Predict the level of BUN in kidney failure
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Higher
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Predict the level of BUN in liver disease
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Lower
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Predict the level of BUN when you eat a lot of protein
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Higher
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Predict the level of BUN when you are over hydrated
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Lower
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Predict the level of BUN in malnutrition
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Inconclusive
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What is hyperammonemia?
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Increase blood levels of ammonia. Can be herditary or aquired.
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How can hyperammonemia be caused by liver disease?
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Liver damage = urea cycle inparied
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