amino acid oxidation Flashcards
are chemical reactions that form intermediates of a metabolic pathway.
anapldrotic reaction
a non-amino acid cofactor that is tightly linked to an enzyme
prosthetic group
true/false: there is a storage compartment for amino acids
false
in the ________, free amino acids are transported through epithelial cells, enter blood capillaries and travel to the liver
small intestine
_____ are the. building blocks in protein synthesis
amino acid
true/false: if amine group is separated from the amino acid during metabolism (as ammonia) it can be toxic to the cell
true
how many amino acids are essential and must be broken down from protein in our diet?
9
during ammonia toxicity, neuronal impairments can arise due to depleted levels of alpha-ketoglutarate. why would this impair the function of neutrons?
a) alpha-ketoglutarate is required for glycolysis
b) alpha-ketoglutarate is a key intermediate in the CAC
c) alpha-ketoglutarate is an antioxidant
d) alpha-ketoglutarate is required for the production of ketone bodies
b
what two things must occur in order to prevent ammonia toxicity?
- ammonia must be removed from the amino aicd
- ammonia must be sent to the liver to be metabolized into a less toxic substance (urea)
these reactions transfer amino groups from an amino acid to a keto acid
transanimation reactions
what cofactor do transanimation reaction usually require
vitamin B6 (pyridoxine)
are transanimation reactions usually reversible or irreversible?
reversible
true/false: malate-asparate shuttle relies on a transaminase
true
cells contain different transaminases that differ in their ______ for the L-amino acid
specificity
all enzyme-catalyzed aminotransfersae reactions remove amino groups from amino acids, producing what byproduct that is important during metabolic stress?
a) pyruvate
b) a hydride and a H+
c) one of the ketone body molecules
d) fumerate
e) an alpha-keto acid
e
this is used as a prosthetic group by all aminotransferases. it carries amino groups at the active side and transfers the amino group to alpha-keto acid
pyridoxine/pyridoxal phosphate (PLP)
which statement about pyramidal phosphate (PLP) is false?
a) it is a coenzyme form of vitamin B6
b) all aminotransferases use it as a prosthetic group
c) it is only used by transaminases and by no other enzymes
d) it recieves amino groups in transamination reactions
c
where does oxidative deamination of glutamate occur
in the mitochondrial matrix (free ammonia in the cytoplasm would damage the cell)
what enzyme is used to catalyze the oxidative deamination of glutamate
L-glutamate dehydrogenase
what is the product of the oxidative deamination of glutamate by L-glutamate dehydrogenase and where can it be used
alpha-ketoglutarate, enters the CAC or glucose synthesis
transdeamination involves
a) the alpha-amino acids from nearly all amino acids being transferred to glutamate by transaminations, followed by the release of NH4+ from glutamate by L-glutamate dehydrogenase
b) release of alpha-amino groups from nearly all amino acids by L-amino acid dehydrogenase’s
c) release of alpha-amino groups from nearly all amino acids by L-amino acid deaminase
d) the combined actions of transaminase and glutamine synthetase
a
glutamate dehydrogenase:
a) converts glutamate to glutamine
b) converts glutamine to glutamate
c) converts glutamate to aspartate
d) dominates glutamate to alpha-ketoglutarate
e) transmainates alpha-ketoglutarate to glutamate
d
