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