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88 Cards in this Set
- Front
- Back
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Action of trypsin.
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C-terminal of Lys or Arg
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Action of chymotrypsin.
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C-terminal of Phe, Leu, Tyr, Trp, Met
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Action of elastase.
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C-termial of Ala, Ser, Gly
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Action of carboxypeptidase.
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C-terminal of ?
Exopeptidase |
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Action of aminopeptidase.
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Exopeptidase @ N-terminus
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What is caused by the persistence of transcytosis?
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food allergies
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What is GGT?
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gamma-glutamyl transpeptidase
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What causes glutathionuria?
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GGT deficiency
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When is there too much GGT?
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bile duct obstructing lesions
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What does the gamma-glutamyl cycle do?
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Brings amino acids into the cell from the outside by connecting it to glutamyl
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What causes oxoprolinuria?
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glutathione synthetase deficiency
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What is GSH?
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Glutathione
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What are the other functions of glutahione?
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Detoxification of xenobiotics
Antioxidant |
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What does methotrexate do?
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Inhibits THF reductase
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What is transamination?
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Transfer of an alpha-amino acid to an alpha-keto acid to make a new alpha-amino acid and a new alpha-keto acid
Helps dispose of amino acids |
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What do ALT & AST require as a cofactor?
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PLP
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What does glutamate dehydrogenase do?
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Either destroys or produces amino acids.
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How is glutamate dehydrogenas regulated?
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Allosterically by ATP/GTP & ADP/GDP
High energy-->make Glu from alpha-KG & free ammonia Low energy-->oxidative deamination of Glu to make NADPH & alpha-KG |
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What does oxidative deamination?
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Glutamate DH
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What are dehydratases & what do they do?
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Deamination enzymes
Deaminate Thr & Ser Dehydrate then deaminate |
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What cofactors do dehydratases require?
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PLP
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What cofactors do hydrolases require?
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None
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What do hydrolases do?
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hydrolysis of amide "N" of Gln & Asn
deamination of His |
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What are the hydrolases?
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Glutaminase
Asparaginase Histidase |
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What is produced by glutaminase?
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Glu + ammonia
Same with asparaginase |
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What is produced by histidase?
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Urocanate + ammonia
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What causes a lack of urocanate in sweat?
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Histidase def. (Histidinemia)
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What urea cycle enzymes are located in the mitochondrial matrix?
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CPSI
OTC N-acetyl glutamate synthase |
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What urea cycle enzymes are located in the cytosol?
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AS
AL Arginase |
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What is transported from the mitochondrial matrix to the cytosol in the urea cycle?
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Citrulline
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What is transported from the cytosol to the mitochondrial matrix in the urea cycle?
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Ornithine
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How is the urea cycle associated with the citric acid cycle?
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Fumarate is produced by the urea cycle & removed by the CAC
Asp is produced by the CAC & used by the urea cycle |
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What does CPSI do?
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urea cycle enzyme
NH4 + CO2 + 2ATP-->carbamoyl phosphate + 2ADP |
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What is the rate-limiting step in the urea cycle?
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CPSI
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How is CPSI regulated?
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Allosterically by N-acetylglutamate
N-acetylglutamate drives the urea cycle after protein consumption to get ride of nitrogen |
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What is a defect in CPSI called?
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Hyperammonemia I
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What is a defect in N-acetylglutamate synthase called?
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Hyperammonemia II
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What is a defect in OTC called?
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Hyperammonemia III
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What is a defect in AS called?
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Citrullinemia
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What is a defect in AL called?
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Argininosuccinicaciduria
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What is a defect in arginase called?
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Argininemia
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What are the major sources of ammonia?
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Glu DH
Glutaminase Purine & pyrimidine metabolism Amino acid deamination Bacterial urease |
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What are the essential amino acids?
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PVT TIM HALL
Phe Val Trp Thr Ile Met His Arg Leu Lys |
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What are the ketogenic amino acids?
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Leu
Lys |
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What are the glucogenic amino acids?
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Ile Phe Tyr Trp
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What are the ketogenic & glucogenic amino acids?
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Met, Thr, Val, Arg, His, Pro, Cys, Ala, Gly, Ser, Asn, Asp, Gln, Glu
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How is alanine synthesized?
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From pyruvate by ALT
Requires PLP |
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How is Asp synthesized?
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From OAA by AST
Requires PLP |
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How is Glu synthesized?
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From alpha-KG by AST
Requires PLP |
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How is Asn synthesized?
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From Glu by Asn synthetase
Requires ATP |
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How is Gln synthesized?
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From Glu by Asn synthetase
Requires ATP |
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How is homocysteine synthesized?
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From Met by 2 steps requiring SAM & ATP
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How is cysteine synthesized?
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From homocysteine by 2 steps requiring PLP & Ser
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How can Met be synthesized?
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From homocysteine
Requires either betaine OR PLP & THF |
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What causes homocystinuria?
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Glutathione-beta-synthase def
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What are the symptoms of homocystinuria?
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defects in collagen-containing tissues
Tx: Met-restricted diet, LOTS of B6 |
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What is B6 the precursor to?
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Ser, Gly, Cys
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What cofactors are needed to synthesize Gly? What is Gly made from?
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PLP, THF
Ser |
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What cofactors are needed to synthesize cystathionine? What is cystathionine made from?
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PLP, homocysteine
Ser |
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How is Arg synthesized?
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From Glu
Glu-->ornithine-->Arg |
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How is GABA synthesized?
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Glu-->GABA by glutamate decarboxylase
Requires PLP |
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What cofactors are needed for Tyr synthesis?
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Tetrahydrobiopterin
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How is Tyr made?
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From phenylalanine by phenylalanine reductase
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What causes phenyketonuria?
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Phe reductase def.
Tetrahydrobiopterin reductase and/or synthetase def. |
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What is the rate-limiting step of heme synthesis?
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ALA synthase
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What are porphyrias?
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reduced activity of heme-synthesizing enzymes
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What is inhibited by Pb?
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ferrochetalases
ALA dehydratase |
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How is creatine formed?
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From Arg & Gly in 2 steps
Requires SAM |
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How is creatine phosphate produced?
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From creatine by creatine kinase
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How is histamine synthesized?
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From Histidine by histidine decarboxylase
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How is serotonin made?
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From Trp in 2 steps
Requires Tetrahydrobiopterin & PLP |
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How is dopamine made?
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From Tyr in 2 steps
Requires Tetrahydrobiopterin & PLP Intermediate=DOPA |
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How is NE made?
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From Tyr in 3 steps
Requires Tetrahydrobiopterin, PLP, and ascorbate Intermediates=dopamine & DOPA |
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How is epinephrine made?
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From Tyr in 4 steps
Requires Tetrahydrobiopterin, PLP, ascorbate, and SAM Intermediates=NE, dopamine, DOPA |
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What is found in the adrenal medulla?
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NE & epinephrine
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What is found in the nervous system from the NE synthesis path?
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dopamine & NE
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How is melanin made?
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From Tyr by tyrosinase
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How are polyamines made?
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from ornithine
Need PLP, SAM |
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What are polyamines?
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Spermidine, spermine
Positively charged |
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How is carnitine made?
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From Lys in 4 steps
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How is NO made?
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From Arg by NOS
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What cofactors are required for NO synthesis?
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NADPH, heme, FAD, FMN, tetrahydrobiopterin, Ca, calmodulin
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What is Hartnup disease?
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Defect in aromatic & neutral AA transport-->Pellagra
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What has indoles in the urine?
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Hartnup
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What is cystinuria?
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Defect in Lys, Cys, Arg, cystine absorption
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What causes albinism?
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Defect in tyrosinase
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What results from a cystathionase defect?
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Cystathionuria
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What is pellagra?
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Dementia
Diarrhea Dermatitis |
