Biochemistry Flashcards
what happens to unused amino acids and why?
they are degraded as there is no storage form for amino acids
what is the main site for amino acid degradation?
the liver
how does absorption of amino acids occur?
broken down from proteins by proteolytic enzymes in stomach and intestine
absorbed into intestinal cells and released into blood for absorption by other tissues
what regulates protein turnover?
AMP kinase
what does breakdown of amino acids produce and why?
ammonia (NH3) and ammonium ions (NH4+)
amino acids contain nitrogen
name three molecules that ammonia/ammonium are excreted in
urea
uric acid
creatinine
where is urea formed?
in the liver
what are the three steps in the synthesis of urea?
transamination
de-amination
urea cycle
what is transamination?
transfer of an amino from an AA to a ketoglutarate to make glutamic acid
what is de-amination?
removal of an amine from glutamic acid to make ammonia
what is the urea cycle?
ammonia is combined with aspartic acid to make urea
what are two major carriers of nitrogen in the blood to the liver?
alanine
glutamine
what happens to the carbon skeletons of amino acids?
they can be converted to glucose or oxidised in the TCA cycle
what do the carbon skeletons of ketogenic amino acids give rise to?
ketone bodies
fatty acids
name three inherited disorders of amino acid degradation
alkaptonuria
maple syrup urine disease
phenylketonuria
