During chronic acidosis, glutaminase is induced in the kidney, which leads to an increase in the amount of ammonium ions excreted.
12.
The first part of the mechanism occurs in the active site of the glutaminase domain and releases an ammonia group from glutamine by hydrolysis.
13.
Glutaminase is expressed and active in periportal hepatocytes, where it generates NH 3 ( ammonia ) for urea synthesis, as does glutamate dehydrogenase.
14.
DON is not approved as pharmaceutical agent, but is tested in combination with a recombinant glutaminase in clinical trials for the treatment of different solid tumors.
15.
Cortisol's only direct effect on the hydrogen-ion excretion of the kidneys is to stimulate the excretion of ammonium ions by deactivating the renal glutaminase enzyme.
16.
The enzyme consists of two domains : a glutaminase domain that produces ammonia from glutamine by hydrolysis and a phosphoribosyltransferase domain that binds the ammonia to ribose-5-phosphate.
17.
There is biochemical evidence that shows rises in ammonia can inhibit glutaminase and therefore limit the rate of synthesis of neurotransmitters such as glutamate, which can explain the developmental delay in argininosuccinic aciduria patients.
18.
Glutaminase can also be found in the intestines, whereby hepatic portal ammonia can reach as high as 0.26 mM ( compared to an arterial blood ammonia of 0.02 mM ).
19.
Phosphate-activated mitochondrial glutaminase ( GLS1 ) is suggested to be linked with elevated metabolism, decreased intracellular reactive oxygen species ( ROS ) levels, and overall decreased DNA oxidation in both normal and stressed cells.
20.
The glutaminase domain is homologous to other N-terminal nucleophile ( Ntn ) hydrolases The free N terminus acts as a base to activate the nucleophile and protonate the leaving group in the hydrolytic reaction, in this case ammonia.
