Term
| Importance of ntirogen metabolism |
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Definition
major contributor to living systems
key component of aa, nucleotieds
biological useful forms are scarce
most living organisms need reduced nitrogen form |
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Term
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Definition
N2 is converted to Ammonia by bacterial fixation
Ammonia is used to synthesize aa in body
Biomolecules are degraded to Ammonia and excreted
The ammonia is nitrited by soil bacteria to Nitrite
Nitrite is nitrated by soil bacteria to form Nitrate
Some nitrates will be denitrated by soil bacteria to N2 others will be reduced by anerobic bacteria (plants) to Ammonia |
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Term
| Ammonia incorporated into biomolecules through |
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Definition
glutamate and glutamine
these are 2 orders higher in mag than any other aa
can now donate amino grp to make other aa
2 step reaction glutamate + NH4 yields glutamine |
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Term
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Definition
| found in all organisms main regulatory enzyme of nitrogen metabolism catalyzes reaction of glutamate to glutamine |
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Term
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Definition
alpha ketoglutarate and glutamine and NADPH yields 2 glutamate +NADP
by glutamate synthase; not present in animals |
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Term
| minor glutamate synthesis pathway |
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Definition
catalyzed by glutamate dehydrogenase all organisms alpha-ketoglutarae + NH4 + NADPH yields glutamate + NADP reverse source of NH4 for the urea cycle
enzyme located in the mito matrix |
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Term
| Allosteric regulation of glutamine synthetase |
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Definition
| glycine, Alanine, Glucosamine-6P, Histidine, CTP, Carbamoyl phosphate, Tryptophan, AMP work synergisticly to obtain effect |
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Term
| Covalent Regulation of Glutamine Synthetase |
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Definition
| both adenylation and deadenylation of glutamine synthetase by adenyltransferase at Tyr397 (ade inhibits) |
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Term
| Regulation of Adenylyltransferase for glutamine synthetase |
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Definition
regulated by binding of regulatory protein P11
the activity of P11 is regulated by uridylyltransferase (UT)
Pii-ump stimulates deadenylation of glutamine synthetase |
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Term
| Uridylylation of Pii regulation |
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Definition
inhibited by binding of glutamine and Pi to UT
stimulated by binding of alpha-ketoglutarate and ATP to Pii |
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Term
| glutamine synthetase regulation by gene expression |
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Definition
uridylylated Pii mediates the activation of transcription of the gene encoding glutamine synthetase increasing cellular concnetration of the enzyme
deuridylation of Pii does the opposite |
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Term
| biosynthesis of glutamate in animals |
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Definition
transamination of alpha-ketoglutarate during amino acid catabolism
carried out by aminotransferases
prosthetic group= PLP
the opposite reaction serves as a universl source of aa through transamination reactions |
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Term
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Definition
| PLP the coenzyme form of pyridoxine (vitamin B6) |
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Term
| key chemical rearrangements in biosynthesis of aa |
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Definition
1. transamination reactions by enzymes containig PLP
2. transfer of 1C group by tetrahydrofolate or SAM
3. transfer of amino groups derived from the amide nitrogen of glutamine |
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Term
| mechanism for glutamine amidotransferases |
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Definition
2 domains glutamine-binding domain and NH3 acceptor domain
glutamine in GBD is attacked by cys in active center hydrolates NH2 making the intermediate
NH3 flows through channel where it reacts with the acceptor to form the aminated product |
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Term
| alpha-ketoglutarate derived aa |
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Definition
glutamate glutamine proline arginine From CAC
alpha- PREQ |
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Term
| 3-Phosphoglycerate derived aa |
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Definition
Serine Glycine Cysteine from glycolysis
3PB=SCG |
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Term
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Definition
aspartate asparagine methionine threonine lysine from CAC
DONT K M |
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Term
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Definition
Alanine Valine Leucine Isoleucine from glycolysis
PAVIL |
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Term
| PEP and erythose 4-phosphate derived aa |
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Definition
tryptophan
phenylaline
tyroxine
from glycolysis and PPP |
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Term
| Ribose 5-phosphate derived aa |
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Definition
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Term
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Definition
Must be obtained from food Valine Leucine Isoleucine Tryptophan Phenylaline Histidine Methionine Threonine Lysine
WTFMHVIL |
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Term
| Conditionally essential amino acids |
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Definition
required to some degree in young, growing or ill animals glutamine proline arginine glycine cysteine tyrosine
QYCGPR |
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Term
| 5-phosphorylbosil-1-pyroposphate (PRPP) |
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Definition
a key intermediate in several pathways of amion acids and nucleotide biosynthesis
links them
synthesized from ribose-5-phosphate from PPP
catalyzed by enzyme ribose phosphate pyrophosphokinae |
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Term
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Definition
from glutamate
key intermediate is glutamate gamma semialdehyde |
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Term
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Definition
arginase converts arginine to ornithine and urea
ornithine is converted to glutamate-gamma-semialdehyde by ornithine delta-aminotransferase |
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Term
| Pathway to biosynthesis of arginine in mammals |
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Definition
ornithine delta-aminotransferase operates in the direction of ornithine formation
converted to citrulline and arginine in the urea cycle |
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Term
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Definition
from 3-Phosphoglycerate
glutamate transfers amino group and releases alpha-ketoglutarate |
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Term
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Definition
From serine by serine hydroxymethyltransferase removes a carbon from serine can be produced in liver of vertebrates from CO2 and NH4 with N5N10-MEthyleneH4folate this releases tetrahdyrofolate
cofactor= PLP needs H4folate |
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Term
| Serine hydroxymethyltransferase |
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Definition
requires H4folate to remove a carbon from serine
accepts the beta carbon of serine and forms a methylene bridge btw N5 and N10 to yield N5,N10 methylenetetrahydrofolate |
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Term
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Definition
from serine and homocysteine
methionine furnishes the sulfur group and serine supplies the carbon skeleton |
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Term
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Definition
| made from methionine via SAM and SAHC |
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Term
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Definition
| amiontransferase reaction of oxaloacetate and glutamate to form alpha-ketoglutarate and aspartate |
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Term
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Definition
| amiontransferase reaction of pyruvate and glutamate forming alpha-ketoglutarte and alanine |
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Term
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Definition
| synthesized by amidation of aspartate with glutamine donating the NH4+ through asparagine synthetase |
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Term
| Methionine, threonine and lysine production |
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Definition
aspartate gives rise to these
branch pt occur at aspartate beta-semialdehyde and homoserine |
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Term
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Definition
| comes from pyruvate and threonine |
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Term
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Definition
shares 4 enzymes with isoleucine
made from pyruvate |
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Term
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Definition
starting pt from alpha-ketoisovalerate an intermediate from the valine pathway
this will then proceed 4 more steps to leucine |
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Term
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Definition
animals do not have these and obtain them from food
2 PEP and 1 erythrose 4-phosphate will make chorismate
will give phenylaline, tyrosine, tryptophan |
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Term
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Definition
| key common intermediate in bosynthesis of tryptophan, tyrosine, and phenylalanine |
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Term
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Definition
from phenylalanine through oxidation by phenylalanine hydroxylase and tyrosine can go to melanin, catecholamines, fumarate, and tissue proteins
can come from chorismate |
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Term
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Definition
deficiency of phenylalanine hydroxylase
instead of phenylaline forming tyrosine it will form phenylpyruvate
phenylpyruvate can be converted to phenyllactate and phenylacetate all toxic substances
CNS: mental retardation, hyperactivity, seizures
hypopigmentation |
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Term
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Definition
derives from 3 precursors
PRPP- contributes C skeleton
ATP- contributes N and a carbon
Glutamine supplies second ring N
ATP acts as a metabolite not energy factor
3 step process:
1. condensation of ATP and PRPP
2.purine/ ribose ring opening leads to N15-Phosphoribulosyl-formimino-5-aminoimidazole-4-carboxamide ribonucleotide
then the formation f the imidazole ring through use of glutamine
AICAR is released and histidine is formed |
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Term
| Sequential feedback inhibition |
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Definition
| interlocking regulatory mechanisms in the biosynthesis of several aa so if 1 enzyme in the system is halted the previous enzymes are also halted |
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Term
| enzyme multiplicity in aa biosynthesis |
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Definition
| prevents one biosynthetic end product from shutting down key steps in a pathway when other products of the same pathway are required |
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Term
| Amino Acids are precurosors for |
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Definition
| hormones, coenzymes, nucleotides, alkaloids, cell wall polymers, porphyrins, antibiotics, pigments and neurotransmitters |
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Term
| AA role in creatine production |
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Definition
synthesized from glycine, arginie and methionine in the form of SAM
glycine + arginine in amidinotransferase then add SAM for a methyl donation to form creatine |
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Term
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Definition
an energy buffer in skeletal muscle
formed from the additon of ATP to creatine by creatine kinase |
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Term
| AA role in glutathione production |
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Definition
gamma-carboxyl group of glutamate and alpha-amino group of cysteine are condensed with ATP
alpha carboxyl of cystein then to glycine with ATP to form Glutathione |
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Term
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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 state
reducing glutaredoxin in deoxyribonucleotide synthesis
redox function used to remove toxic peroxides |
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Term
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Definition
enzyme used to catalyze the redox function of glutathione in peroxide removal
contains selenocystein for enzymatic activity |
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Term
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Definition
(dopamine > norep > epi)
from tyrosine
important cofactor in this process is PLP and enzyme aromatic amion acid decarboxylase |
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Term
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Definition
from amino acid glutamate by decarboxylation
cofactor is PLP enzyme is glutamate decarboxylase |
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Term
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Definition
from the aa tryptophan
2 step process needs the aromatic aa decarboxylase enzyme and cofactor PLP |
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Term
| biosynthesis of histamine |
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Definition
from aa histidine
decarboxylatd by histidine decarboxylase; cofactor PLP |
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Term
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Definition
strucutral analog of histamine
prominent example of histamine receptor antagonist
promotes healing of duodenal ulcers by inhibitng secretion of gastric acid |
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Term
| Biosynthesis of nitric oxide |
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Definition
from aa arginine
plays a role in neurotransmission, blood cloting and blood pressure
2 steps are catalyzed by nitric oxide synthase
reaction is a 5e oxidation
4 cofactors FMN, FAD, tetrahydrobiopterin and Fe3+ heme |
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Term
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Definition
| dimeric enzyme structurally related to NADPH cytochrome P-450 reductase |
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Term
| Spermine and Spermidine biosynthesis |
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Definition
involved in DNA packaging derived from methionine and ornithine
1. decarboxylation of ornithine by PLP (ornithine decarboxylase) forming putrescine
2.SAM then acts as a source of proplyamino groups transfer onto putrescine
3. catalyzed by propylaminotransferase I and II to form spermidine then spermine |
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Term
| Treating African Sleep Sickness |
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Definition
includes the use of mechanism-based suicide enzyme inactivators
targets polyamine biosynthesis in Trypanosoma cells (protist)
target is ornithine decarboxylase blocked by DFMO |
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Term
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Definition
structural analog of ornithine
inhibitor of ornithine decarboxylase
acts by providing an alternative electron sink in the form of 2 strategically placed flourine atoms
S of a Cys forms a covalent complex with the highly reactive PLP-inhibitor adduct in an essentially irreversible reaction |
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