Function 
Glutaminase (GLN) catalyzes the conversion of glutamine (Gln) to glutamic acid (Glu).  GLN is present at the axonal termini of neurons where GA functions as a neurotransmitter.  ADP is an activator of GLN.  GLN is a homodimer[1].  In human GLN is found as 2 isozymes – GLN and GLN 2. 
- K-GLN is the kidney isoform
 - L-GLN is the liver isoform.  
 -  Glutaminase-asparaginase (GLN-ASN) can amidohydrolase both glutamine and asparagine to their corresponding Glu and Asp[2].  For details on GLN-ASN see Glutaminase-Asparaginase (Pseudomonas 7A).
 
 Relevance
Cancer cells show elevated GLN activity[3].  Hepatic GLN increases during starvation, diabetes and feeding a high protein diet while kidney-type GLN increases in kidney during metabolic acidosis[4].
  Structural highlights 
The glutamate binding site is in the helical domain of GLN and [5]. .
 3D structures of glutaminase
Glutaminase 3D structures