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27 Cards in this Set
- Front
- Back
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What are the 10 essential amino acids?
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Arginine, Histidine, Isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine (PVT TIM HALL)
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What AA is used to synthesize tyrosine?
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phenylalanine
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What AA is used to synthesize glycine?
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threonine
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What is substrate used to form alanine and what enzyme?
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a-ketoacid pyruvate is converted into alanine by aminotransferase
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What are the two amino acids that do not use aminotransferase reactions?
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threonine and lysine
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What amino acid can alpha-ketoacid oxaloacetate be converted into using aminotransferase rxn?
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aspartate
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What AA can be formed into asparagine and what enzyme performs the reaction?
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Aspartate can be converted to asparagine vua asparagine synthase but requires glutamine and atp to be consumed in the reaction
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What is formed in the liver when free ammonia is incorporated into alpha-ketoglutarate? What enzyme performs this reaction?
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Glutamate is formed in this reaction via glutamate dehydrogenase; This rxn is reversible which makes glutamate the “gateway” between amino groups of amino acids and free ammonia
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What AA can form glutamine and what enzyme is used?
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glutamate can be converted into glutamine using glutamine synthase. Atp is consumed
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What product of glycolysis can be formed into serine and how?
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3-Phosphoglycerate. It is oxidized to 3-phosphopyruvate.
3-Phosphopyruvate undergoes aminotransfer to form 3-phosphoserine. 3-Phosphoserine is dephophorylated to form serine |
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What two AA can be used to synthesize cysteine?
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met and ser
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How is met converted to cysteine?
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In the first step, the essential aa met and ATP are used by methionine adenosyltransferase to produce S-adenosylmethionine (SAM aka AdoMet). A methyltransferase removes the methyl group from SAM leaving S-adenosylhomocysteine.
S-adenosylhomocysteine is cleaved by adenosylhomocysteinase to form homosysteine (one carbon longer than cysteine) and adenosine. Homocysteine is thioether linked to Ser by cystathionine synthase to form cystathionine. Cystathionine is cleaved by cystathionase to form cysteine and a-ketobutyrate. |
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What AA can be made into proline and arginine?
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glutamate
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If arg is produced by the body, why is it an essential aa?
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it is classified as an essential aa because it is synthesized in quantities too low to support growth of a young person
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How is proline formed from glutamate?
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Glutamate semialdehyde will spontaneously cyclize and dehydrate without the aid of any enzymes to form D1pyrroline-5-carboxylate.
The delta1 site of unsaturation is reduced to form proline. |
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What converts glutamate semialdehyde to ornithine?
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aminotransferase
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Where does the production of arg primarily occur and why?
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in the kidneys because they lack arginase and therefore cannot break down arginine into ornithine and urea
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In the kidney mt matrix, what are ornithine and carbamoyl phosphate converted to?
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citrulline via ornithine transcarbamoylase
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What happens to citrulline in the mt matrix?
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transported out of the mt to the cytosol to finish the later rxns
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What forms argininosuccinate?
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citrulline via argininosuccinate synthase with ATP and asp
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What are the products formed when argininosuccinate lyase cleaves argininosuccinate?
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fumarate and arginine
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What is arg in the kidneys used for?
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synthesize proteins
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What is fumarate in the kidneys used for?
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generate glycose, ATP, aspartate
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What is the function of the urea cycle?
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eliminate nitrogenous waste (ammonium) from the body in the form of urea
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Where is the primary site of production of urea?
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liver
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What forms carbamoyl phosphate?
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Bicarbonate and ammonium ions via carbomyl phosphate synthetase I (costs 2 ATP)
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What is the cost of eliminating nitrogen from the body?
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4 atp
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