Glutaminase

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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


Human glutaminase tetramer complex with glutamate 3unw

Drag the structure with the mouse to rotate

ReferencesReferences

  1. Curthoys NP. Role of mitochondrial glutaminase in rat renal glutamine metabolism. J Nutr. 2001 Sep;131(9 Suppl):2491S-5S; discussion 2496S-7S. PMID:11533299
  2. Steckel J, Roberts J, Philips FS, Chou TC. Kinetic properties and inhibition of Acinetobacter glutaminase-asparaginase. Biochem Pharmacol. 1983 Mar 15;32(6):971-7. PMID:6838661
  3. Erickson JW, Cerione RA. Glutaminase: a hot spot for regulation of cancer cell metabolism? Oncotarget. 2010 Dec;1(8):734-40. PMID:21234284 doi:http://dx.doi.org/10.18632/oncotarget.208
  4. Curthoys NP, Watford M. Regulation of glutaminase activity and glutamine metabolism. Annu Rev Nutr. 1995;15:133-59. PMID:8527215 doi:http://dx.doi.org/10.1146/annurev.nu.15.070195.001025
  5. Delabarre B, Gross S, Fang C, Gao Y, Jha A, Jiang F, Song J J, Wei W, Hurov JB. Full-Length Human Glutaminase in Complex with an Allosteric Inhibitor. Biochemistry. 2011 Nov 18. PMID:22049910 doi:10.1021/bi201613d

Created with the participation of Lindsey Butler.

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