Green (Delidow) - Amino Acids Flashcards
Dr. Green lecture from 2012 on same topic as Dr. Delidow's lectures this test
What is formed when amino acids lose their amino groups?
a-Keto Acid
Where do the amino groups head in AA degradation?
Carbon skeletons?
Amino groups head for biosynthetic pathways, or the urea cycle through carbamoyl phosphate
Carbon skeletons are converted to a-Keto Acids and enter the citric acid cyle
Where does amino group catabolism occur?
Liver
What does muscle send to the liver to enter amino acid catabolism?
Alanine, Glutamine
What removes the amino group from AAs?
Aminotransferase
Transaminase
What is the amino group usually transfered to once removed from an AA?
What does this require?
Transfered to a-Ketoglutarate to form glutamate
Pyridoxal Phosphate (PLP) coenzyme
What is the most common acceptor (and eventual donor) of amino groups?
Glutamate
Aside from Glutamate, what other AA can serve as aminotransferases?
Alanine to Pyruvate
Aspartate to Oxaloacetate
Where does oxidative deamination occur?
What catalyzes the reaction?
Final products?
Mitochondria
Glutamate Dehydrogenase
a-ketoglutarate / ammonia
What is a direct source of ammonia nitrogen for the urea cycle?
What other AA can provide the ammonia?
Glutamate dehydrogenase release of ammonia
Serine, threonine, glutamine
What is the destination of the a-ketoglutarate once ammonia removed?
Citric Acid Cycle
Glucose Synthesis
How is Glutamate Dehydrogenase regulated?
Activate: Low Energy
Inhibit: High Energy
How is ammonia formed in muscle transported to liver?
Glutamine, Alanine
Where is ammonia converted to urea?
Mitochondria
What can reduced liver function (inherited or acquired) cause?
Ammonia Intoxication, tremors, slurred speech, blurry vision
Where does the urea cycle occur?
Begins inside mitochondria, but subsequent steps take place in cytosol
What is the first step in the urea cycle?
What does this product donate to create?
Ammonia and CO2 form carbamoyl phosphate
Carbamoyl Phosphate donates carbomyl group to ornithine to form citrulline
What combines with citrulline in the urea cycle?
What occurs to this product?
What occurs to this next product?
Citrulline combines with aspartate to form arginosuccinate
Argininosuccinate cleaved to release arginine and create fumarate
Arginine cleaved to yield urea and ornithine
What is the main regulatory enzyme of the Urea Cycle?
Carbamoyl Phosphat Synthetase I (CPS I)
Activate: N-Acetylglutamate
What are the sources of the Nitrogen (x 2) and Oxygen in Urea?
Nitrogens: Ammonia, Aspartate
Oxygen: CO2 , H2O
What can increas the synthesis and activity of the urea cycle enzymes?
High protein diet
starvation
What links the Urea Cycle to the CAC?
What can these be converted to?
Aspartate and Fumarate
Fumarate: Converted to Malate
What cofactors are required to prepare the carbon skeletons to enter the Citric Acid Cycle?
THF, SAM
Tetrahydrobiopterin
What AAs can form pyruvate?
Alanine
Serine
Cysteine
Glycine
Threonine
Tryptophan
All Sexy Chicas Get Trashy Tattoos
Where are BCAAs (Isoleucine, Leucine, Valine) metabolized?
Muscle
What are limiting AA during periods of tisue growth?
Histidine
Arginine
AA Derived from Glutamate
Glutamine
Arginine
Proline
GLUTE GAP
AA Derived from Serine
Glycine
Cysteine
Ser Glyde Cyster
AA Derived from Aspartate
Methionine, Asparagine, Lysine, Threonine
Aspartate MALT
AA Derived from Pyruvate
Valine, Alanine, Isoleucine, Leucine
Pyruvate VAIL
Where are major sites of heme synthesis
Liver (cytochromes)
RBCs (Hb)
PKU
Defect in Phenylalanine Hydroxylase
Inability to convert phenylalanine to tyrosine
Screened in babies, special diet
Alkaptonuria
Defect in homogentisate 1,2-dioxygenase
Conversion of homgentisate to maleylacetoacetate
Buildup of homogentisate, black urine
Alanine is converted to what in the liver?
Pyruvate
What are the ketogenic AAs?
Leucine, Lysine
What AAs are ketogenic and glucogenic?
PITT
Phenylalanine
Isoleucine
Tryptophan
Tyrosine
What type of reaction is involved in Histamine synthesis
Decarboxylation
What is most likely to result from lead poisoning?
Erythropoeietic protoporphyria
What is most abundant AA in body?
Glutamine
