Amino Acid Metabolism EC Flashcards
Nitrogen containing substances are used in the synthesis of what compounds?
Nucleotides Neurotransmitters Hormones Porphyrins Nonessential amino acids
What are the essential amino acids?
Phenylalanine Valine Tryptophan Threonine Isoleucine Methionine Histidine Leucine Lysine
Which amino acids are acidic?
Aspartate
Glutamate
Tremor, slurred speech, somnolence, vomiting, cerebral edema, and blurred vision
Ammonia intoxication
Liver disease or urea cycle enzyme deficiency
NH4 accumulates and depletes a-ketoglutarate (blocks TCA)
What happens to carbon skeletons of amino acids after the ammonia has been removed?
They are degraded and become intermediates in the TCA cycle
Some are ketogenic: Lysine & Leucine
Some are both: Isoleucine, Phenylalanine, Typrtophan, & Tyrosine
Some are glucogenic: rest
Tyrosine derivatives
Thyroid hormones
DOPA (dopamine, NE/Epi, melanin)
Methionine
S-Adenosylmethionine (SAM) - methyl group transfers
Homocysteine
Cysteine
Tryptophan
Niacin
Serotonin
Melatonin
Glutamate
GABA
Glutathione
Glycine
Porphyrin (heme)
Arginine
Creatine
NO
Urea
Histidine
Histamine
Phenylalanine
Tyrosine (dopa, thyroid hormones)
What does phenylalanine hydroxylase do?
Convert Phenylalanine to Tyrosine
Man presents with knee and back pain. Dark spots on conjunctiva and nasal bridge. Urine turns dark if forgets to flush.
Alkaptonuria
Defective homogentisic acid oxidase (degrades tyrosine)
Tyrosine, Phenylalanine, and Homogentisic acid build up