Term
| aminotransferases (transaminases) |
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Definition
| alpha amino acids --> alpha keto acids |
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Term
Glutamine Synthetase (equation) |
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Definition
| glutamate + NH4+ + ATP → glutamine + ADP + Pi + H+ |
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Term
Where is glutamate synthase present? |
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Definition
| Plants and bacteria, not present in animals |
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Term
| the equation for glutamate synthase |
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Definition
a-ketoglutarate + glutamine + NADPH + H+→ 2 glutamate + NADP+ |
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Term
| where is glutamate dehydrogenase found |
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Definition
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Term
| what is the equation for glutamate dehydrogenase |
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Definition
| a-ketoglutarate + NH4+ + NADPH ↔ glutamate + NADP+ |
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Term
| how is glutamine synthetase allosterically regulated |
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Definition
| by alanine, glycine, and six end products of glutamine metabolism (AMP, Tryptophan, Carbamoyl phosphate, CTP, Histidine, Glucosamine 6-phosphate) |
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Term
| what is synergistic regulation |
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Definition
| each inhibitor alone produces only partial inhibition, but the effects of multiple inhibitors is greater |
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Term
| adenylation at Tyr397 ______ enzymatic activity of glutamine synthetase |
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Definition
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Term
| AT + Pii-UMP leads to what? |
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Definition
| deadenylation of Glutamine synthetase and its activation |
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Term
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Definition
| adenylation of glutamine synthetase and its inactivation |
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Term
| What two things inhibit Uridyltransferase (UT) |
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Definition
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Term
| What two things stimulate UT? |
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Definition
| alpha-ketoglutarate + ATP |
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Term
| Pii and its relations with transcription of the glutamine synthetase gene |
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Definition
| Pii inhibts transcription of glutamine synthetase gene and uridylylated Pii activates it |
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Term
| Transamination reactions are carried out by enzymes containing what? |
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Definition
| Pyridoxal phosphate (PLP)...it's aminated form is pyridoxamine phosphate |
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Term
| Transfer of one carbon groups is carried out by which two compounds |
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Definition
| tetrahydrofolate and S-adenosylmethionine as cofactor |
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Term
| transfer of amino groups derived from amide nitrogen of glutamine is carried out by what? |
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Definition
| enzymes known as glutamine amidotransferases |
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Term
| what are the two domains for glutamine amidotransferases |
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Definition
| glutamine binding domain (with Cys in the active center), NH3 acceptor domain |
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Term
The g-amido nitrogen of glutamine (red) is released as NH3 in a reaction that involves a covalent _____________ |
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Definition
| glutamyl enzyme intermediate |
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Term
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Definition
| acts in a similar way to glutamine amidotransferase, but uses H2O as the second substrate yeilding NH4+ and glutamate |
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Term
| Ribose-5 phosphate (from the pentose phosphate pathway) + ATP --> |
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Definition
| 5-phosphorybosil-1-pyrophosphate (PRPP) + AMP |
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Term
| the formation of PRPP is catalyzed by what enzyme? |
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Definition
| ribose phosphate pyrophosphokinase |
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Term
| alpha-Ketoglutarate gives rise to what four things? |
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Definition
| glutamate -->glutamine, proline, arginine |
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Term
| arginine is made directly from glutamate in...? |
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Definition
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Term
| important steps in the biosynthesis of arginine from glutamate in bacteria |
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Definition
eventually ornithine is formed Ornithine-->L-Citrulline-->Argininosuccinate-->Arginine |
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Term
| ornithine d-aminotransferase |
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Definition
converts Glutamate y-semialdehyde to Ornithine and vice versa When arginine form diet or protein turnover is insufficient for protein synthesis, it operates in the direction of ornithine formation, which is then converted to citrulline and arginine in the urea cycle |
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Term
| What amino acids are derived form 3-phosphoglycerate |
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Definition
| 3-phosphoglycerate ->Serine-->Glycine and Cysteine |
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Term
Glycine Synthase (Glycine Cleavage Enzyme) |
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Definition
In the liver of vertebrates, glycine is also made from CO2 and NH4+ |
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Term
| To generate cysteine ______ furnishes the sulfur atom and ________ supplies the carbon skeleton |
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Definition
| Methionine furnishes the sulfur artom and serine supplies the carbon skeleton |
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Term
| What is synthesiszed from methionine in mammals |
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Definition
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Term
| What two compounds are used to help make homocysteine from methionine? |
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Definition
| S-adenosylmethionine, and S-adenosylhomocysteine |
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Term
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Definition
| ↔ a-ketoglutarate + alanine |
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Term
oxaloacetate + glutamate ↔ |
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Definition
| ↔ a-ketoglutarate + aspartate |
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Term
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Definition
| aspartate + glutamine ↔ asparagine + glutamate |
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Term
| Oxaloacecetate-->Aspartate--> (4 amino acids) |
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Definition
| Asparagine (N), Methionine (M), Lysine (K), Threonine (T) (precursor of isoleucine) |
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Term
| Pyruvate --> (4 amino acids) |
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Definition
| Alanine (A), Valine (V), Leucine (L), Isoleucine (I) |
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Term
| Chorismate is a key common intermediate in biosynthesis of what 3 amino acids? |
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Definition
| tryptophan, tyrosine, and phenylalanine |
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Term
| Carbon atoms in the benzene ring of Chorismate can be traced to both ____ and _____ |
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Definition
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Term
| Biosyntheis of tryptophan |
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Definition
*PRPP (pink) condenses with antranilate and provide two carbon atoms for indole ring of tryptophan tryptophan synthase has a2b2 subunit structure [image] |
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Term
| What are the three precursors from which Histidine is derived in bacteria and plants |
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Definition
PRPP contributes five carbons ATP contributes a nitrogen and a carbon glutamine supplies the second ring nitrogen (AICAR) is a remnant of ATP: it is released at a later stage
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Term
| which amino acid is a precursor of porphyrins |
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Definition
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Term
| What is creatine synthesized from? |
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Definition
Creatine is synthesized from glycine and arginine, methionine in the form of S-adenosylmethionine, acts as a methyl group donor |
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Term
| Glutathione (GSH) is made from what 3 amino acids? |
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Definition
| Glutamate, cysteine, and glycine |
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Term
| What is Glutathione (GSH) used for |
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Definition
serves as a redox buffer, maintaining sulfhydryl groups of proteins in the reduced state, the iron of heme in the ferrous (Fe2+) state and reducing glutaredoxin in deoxyribonucleotide synthesis Its redox function is also used to remove toxic peroxides: |
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Term
| Tyrosine gives rise to what neurotransmitters |
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Definition
| Catecholamines (dopamine, norepinephrine, and epinephrine) |
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Term
| Glutamate is decarboxylated into what neurotransmitter? |
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Definition
g-aminobutyrate (GABA), an inhibitory neurotransmitter underproduction of this is associated with epileptic seizures |
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Term
| Tryptophan is converted into what neurotransmitter? |
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Definition
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Term
| Parkinson's disease is associated with what? |
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Definition
Underproduction of dopamine and is treated with administering of L-dopa |
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Term
| Histidine is decarboxylated to what? |
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Definition
| Histamine, by histidine decarboxylase |
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Term
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Definition
- a structural analog of histamine
- a prominent example of histamine receptor antagonist
- promotes the healting of duodenal ulcers by inhibiting secretion of gastic acid
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Term
| Nitric Oxide (NO) is biosynthesized from what amino acid and how? |
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Definition
Both steps in biosynthesis of NO from arginine are catalyzed by nitric oxide synthase The enzyme is activated by interaction with Ca2+ - calmodulin Nitric oxide synthase enzyme is related to NADPH cytochrome P-450 reductase |
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Term
Polyamines spermine and spermidine are derived from what two amino acids? What are the steps in the biosynthesis of these polyamines |
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Definition
Methionine and Ornithine
The first step of the pathway is decarboxylation of ornithine, a precursor of arginine, by a PLP-requiring enzyme ornithine decarboxylase This enzyme is a target of several powerful pharmaceutical inhibitors |
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Term
What enzyme is targeted in treating African Sleeping Sickness? What medication is used? |
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Definition
The goal is targeting ornithine decarboxylase, which undergoes a rapid turnover in mammalian,but is stable in protist cells. Difluoromethylomithine (DFMO) - the inhibitor provides an alternative electron sink in the form of two fluorine atoms |
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