Unit 2: Protein and Nucleic Acid Biochemistry Flashcards
______ > _______ (cystathion-gamma-lyase)
cystathione; cysteine
______ is an allosteric activator of N-acetylglutamate synthase.
Arginine
______ is an amino acid used to carry nitrogen to the liver from peripheral tissues.
Glutamine
_______ > ________ (cystathione-beta-synthase)
homocysteine; cystathione
_______ is an allosteric activator of carbamoyl phosphate synthetase 1.
N-acetylglutamate
________ > _________ (Glu dehydrogenase)
Glutamate; alpha-ketoglutarate, ammonia
_____: inherited defects in heme synthesis
porphyrias
dTTP synthesis: UDP > ____ > ____ > ___> dTTP
dUDP; dUMP; dTMP
Excess enzymatic acitivty of _______ may result in overproduction of uric acid and subsequent gout.
Xanthine oxidase
Glutathione ______ may be involved in detoxification, drug resistance, and tumors
Glutathione-S-transferase
Glutathione ______ mutations may lead to heme problems
Glutathione reductase
Glutathione ________ mutations may lead to higher cancer risk.
Glutathione peroxidase
Hyperhomocyteinemia can result from deficiencies of ______ (3).
B6, B12, folate
In _____ degradation, the base is opened and used in other pathways while in ______ degradation, uric acid is produced and excreted in the urine
Pyrimidine; Purine
In _____ synthesis, the base is pre-synthesized and then attached to the sugar
Pyrimidine
In _____ synthesis, the base is synthesized directly on the sugar.
Purine
In Lesch-Nyhan disease, levels of _____ are increased, while levels of _____ are decreased.
PRPP; GMP, IMP
In nitrogen metabolism, arginine may be converted to _________. (3)
ornithine, citrulline (NO), creatine phosphate
Inability to synthesize new dNTPs in SCID results from inhibition of _______.
Ribonucleotide Reductase
Muscle converts pyruvate to _______ to transport nitrogen to the liver.
alanine
Name 3 enzymes that require BH4 as a cofactor.
Tyrosine hydroxylase, tryptophan hydroxylase, phenylalanine hydroxylase
Name 5 sources of atoms in purine synthesis
Glycine, glutamine, aspartate, THF, carbon dioxide
Name a potential treatment for cysteinuria.
Acetazolamide
Name a potential treatment for homocysteinuria.
Vitamin B6
Name activators (2) and inhibitors (2) of Glu dehydrogenase
ADP, GDP; ATP, GTP
Name amino acids that can undergo ketogenic or glucogenic metabolism (4)
Isoleucine, tryptophan, phenylalanine, tyrosine
Name the enzyme complex responsible for elevated alpha-keto acids in Maple Syrup Urine Disease (MSUD)
Branched-Chain alpha-keto-acid dehydrogenase complex
Name the inputs for the urea cycle (4).
Ammonium, ATP, aspartate, bicarbonate
Name the outputs of the urea cycle (4).
P, ADP/AMP, fumarate, urea
Name the primary ketogenic amino acids. (2)
Leucine, lysine
Name two special amino acids that are important to collagen synthesis.
Hydroxyproline, hydroxylysine
Name two unique enzymes involved in branched amino acid metabolism.
Branched-chain aminotransferase (deamination); Branched-chain alpha-keto-acid dehydrogenase complex (decarboxylation)
Phenylalanine > _______ (_______) > ________ (_______)»_space;> catecholamines and melanin
Tyrosine; Phenylalanine hydroxylase; DOPA; Tyrosine hydroxylase
Urea Cycle: Arginine > _______ (________)
Urea, Ornithine; Arginase
Urea Cycle: Argininosuccinate > _______ (_______)
Arginine; Argininosuccinate lyase
Urea Cycle: Citrulline + _______ > ________ (________)
Aspartate; Argininosuccinate; argininosuccinate synthase
Urea Cycle: Ornithine > ________ (_________)
citrulline; carbamoyl phosphate synthetase 1
Vitamin B6 is a precursor for _______, which holds and transfers amino groups on aminotransferases
pyridoxal phosphate (PLP)
Vitamin K is an important cofactor for ________ (enzyme)
glutamyl carboxylase
What byproducts are produced in PKU? Which has a distinctive smell?
Phenylacetate, phenyllactate, phenylpyruvate; phenyllactate
What carbon donor methylates cytosine residues in DNA and methylates norepinephrine to epinephrine?
S-adenosylmethionine (SAM)
What enzyme deficiency is responsible for homocysteinuria?
cystathione-beta-synthase (CBS)
What enzyme is involved in metabolism of tryptophan? What cofactor is required?
Tryptophan hydroxylase; tetrahydrobiopterin/BH4
What is the biochemical defect that results from vitamin C deficiency in scurvy?
Inability to synthesize hydroxyproline and hydroxylysine
What is the biochemical defect that results in phenylketonuria?
Phenyalanine Hydroxylase Deficiency
What is the biochemical etiology of cysteinuria that can cause renal stones?
Defective cysteine transporter
What is the first base produced in de novo purine synthesis?
Inositol monophosphate (IMP)
What is the first base produced in de novo pyrimidine synthesis?
Uracil monophosphate (UMP)
What is the inheritance pattern for Lesch-Nyhan Disease?
Autosomal Recessive
What is the key regulated enzyme in de novo purine synthesis?
Glutamine Phosphoribosyl pyrophosphate Amidotransferase
What is the key regulated enzyme in de novo pyrimidine synthesis?
carbamoyl phosphate synthetase II
What is the secondary key regulated enzyme in de novo purine synthesis?
PRPP synthase
Which amino acid is a precursor for serotonine, melatonin, and niacin?
Tryptophan
Which amino acid is used to produce SAM?
methionine
Which amino acid is used to synthesize T4/thyroxine?
Tyrosine
Which enzyme is deficient in Lesch-Nyhan Syndrome? What is the effect on de novo purine synthesis?
HGPRT (Hypoxanthine-Guanine Phosphoribosyltransferase); increased de novo synthesis
Which enzyme is mutated in Severe Common Immunodeficiency (SCID)? What builds up as a consequence?
Adenosine Deaminase; dATP
Which enzyme? GSH > GSSG
Glutathione peroxidase
Which enzyme? GSSG > GSH
Glutathione reductase
Which important cofactor is responsible for holding and transfering groups on aminotransferases?
pyridoxal phosphate (PLP)
Which metal is required as a cofactor in heme metabolism (delta-aminolevulinate dehydratase)?
Zinc
Which molecule is recycled in the urea cycle?
Ornithine
Which molecule is used in deoxyribonucleotide synthesis? What substrates must be used?
Ribonucleotide Reductase; NDPs
Which molecules serve as nitrogen donors to urea in the urea cycle?
Aspartate, ammonium
Which pathologic pattern? Swollen gums, bruising, anemia; collagen defects
Scurvy
Which pathologic pattern? Uric acid crystal deposition, self-mutilating behavior, severe mental disorders
Lesch-Nyhan Syndrome
Which peptide maitnains iron in the ferrous state?
Glutathione (GSH)
Which protein degradation mechanism is ATP-dependent?
Ubiquitination-Proteasome
Which protein degradation mechanism is ATP-independent?
Lysosomal Degradation
Which special amino acid is important for targeting proteins to membranes by calcium chelations?
Gamma-carboxyglutamate
Which special amino acid is important in collagen hydrogen bonding and strength?
Hydroxyproline
Which special amino acid is important in collagen interchain crosslinks?
Hydroxylysine
Which special amino acid is important in prothrombin?
Gamma-carboxyglutamate
Which urea cycle reaction occurs in the mitochondria? Which enzyme catalyzes this reaction?
Conversion of ornithine to citrulline by carbamoyl phosphate synthetase 1