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37 Cards in this Set
- Front
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transaminase reaction
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produces a-keto acids and glutamate from amino acids and a-ketoglutarate emoves the alpha amino group of most amino acids and transfers it to alpha-ketoglutarate. This forms an alpha keto acid (a former amino acid lacking the amino group but still containing the carbon backbone, carboxylic acid, and R group) and glutamate.
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reactants and products of transaminases ALT
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ALT catalyzes the transfer of the amino group of alanine and the presence of alpha ketoglutarate to form pyruvate and glutamate.
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reactants and products of transaminases AST
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AST transfers the amino groups of glutamate to oxaloacetate which forms aspartate which is a source of nitrogen in the urea cycle.
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Know how the balance of glutamate and a-ketoglutarate is controlled by glutamate dehydrogenase. Know that rapid oxidative deamination of glutamate results in the formation of ammonia
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Oxidative deamination of Glutamate via glutamate dehydrogenase results in the formation of a free ammonia group and an alpha ketoglutarate.
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coenzymes involved in transamination and oxidative or reductive deamination.
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Glutamate dehydrogenase can use either NAD+ or NADP+ as coenzymes. Amino transferases use the coenzyme pyridoxal phosphate. Tetrahydrofolate and tetrahydrobiotin are also used.
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allosteric inhibitor of glutamate dehydrogenase.
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GTP is an allosteric inhibitor of glutamate dehydrogenase. When energy levels are low, amino acid degradation by glutamate dehydrogenase is high which facilitates energy production from the carbon skeletons of amino acids.
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7 intermediates produced from the carbon skeleton of AA
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pyruvate, acetoacetyl CoA, oxaloacetate, acetyl coa, fumarate, alpha ketogultarate, succinyl coa
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amino acid source of pyruvate
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Serine, glycine, Cysteine, Alanine, Threonine
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amino acid source of acetoacetyl coa
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Leucine, Lysine, Tryptophan
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amino acid source of oxaloacetate
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Asparagine, aspartate
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amino acid source of fumarate
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phenylalanine, tyrosine
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amino acid source of alpha ketogluarate
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histidine, proline, glutamate, glutamine
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amino acid source of succinyl coa
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Valine, isoleucine, threonine, methionine
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amino acid source of acetyl coa
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Serine, glycine, Cysteine, Alanine, Threonine
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definition of ketogenic and examples
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Ketogenic- amino acids whose catabolism yields either acetoacetate or one of its precursors. Leucine, lysine.
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definition of glucogenic and examples
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Glucogenic- amino acids whose catabolism yields pyruvate or one of the intermediates of the citric acid cycle. Alanine, arginine, asparagine, aspartate, cysteine, glutamate, glutamine, glycine, proline serine, histidine, methionine, threonine, valine.
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definition of essential amino acids
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Essential amino acids must be obtained in the diet
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definition of non essential amino acids
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amino acids that can be synthesized
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non-essential amino acids
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a. Ala, Arg, Asp, Asn, Cys, Glu, Gln, Gly, Pro, Ser, Tyr
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essential amino acids
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1. Met, Thr (non-polar, polar), ile, leu, val (BCAA's), Phe, trp (aromatic), his, lys (basic)
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precursors and reactions for the formation of glutamate
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alpha-ketoglutarate- transamination
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precursors and reactions for the formation of aspartate
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oxaloacetate- transamination
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precursors and reactions for the formation of tyrosine
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phenylalanine- synthesized from another amino acid
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precursors and reactions for the formation of alanine
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pyruvic acid- transamination
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precursors and reactions for the formation of cysteine
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methionine- synthesized from another amino acid
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source of ser
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3-phosphoglycerate
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source of gly
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Serine
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source of asn
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oxaloacetate
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source of gln
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alpha-ketoglutarate
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role of homocysteine in production of cysteine and routes for disposal
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homocysteine combines with serine to form cystathionine which is hydrolyzed to form cysteine. Deficiency in cystathionine synthase causes an accumulation of homocysteine in the urine and an accumulation of methionine in the blood. Treatment includes restriction of methionine and B6 B12 and folate intake
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hormones and pigments derived from tyrosine
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Pigment: melanin
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Understand how muscles eliminate nitrogen while replenishing their energy supply using the alanine
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glucose cycle and ALT (pyruvate –––> alanine : muscle -> blood -> liver; ––> pyruvate –––> glucose : liver -> blood -> muscle)
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fate of the ammonia in the urea cycle, and the rate-limiting step of that cycle.
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Ammonia is eventually transferred to urea which is then excreted. Carbamoyl phosphate synthetase I is the rate limiting enzyme and requires NAG.
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metabolic basis for phenylketonuria
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genetic defect in phenylalanine hydroxylase
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basis for albinism
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lack of melanin production due to mutations in the tyrosinase gene
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basis for homocystinuria
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deficiency in an enyme involved in cysteine synthesis
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maple syrup disease basis
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error in catabolism of BCAA's
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