The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
 
 
 

Hydrolysis of the brain dipeptide N-acetyl-L-aspartyl-L-glutamate. Identification and characterization of a novel N-acetylated alpha-linked acidic dipeptidase activity from rat brain.

High performance liquid chromatography studies documented the presence of an enzyme activity, N-acetylated alpha-linked acidic dipeptidase (NAALA dipeptidase), in rat brain membranes that cleaves the endogenous brain dipeptide, N-acetyl-L-aspartyl-L-glutamate to N-acetyl-aspartate and glutamate. With ion exchange chromatography, which quantitatively separated [3,4-3H]glutamate from N-acetyl-L-aspartyl-L-[3,4-3H]glutamate, we found that NAALA dipeptidase activity was essentially restricted to nervous tissue and kidney. We characterized NAALA dipeptidase activity in lysed synaptosomal membranes obtained from rat forebrain. Membrane-bound NAALA dipeptidase activity was optimal between pH 6.0 and 7.4 at 37 degrees C. Eadie-Hofstee analysis of kinetic data revealed a rather high apparent affinity for N-acetyl-L-aspartyl-L-glutamate with a Km = 540 nM and a Vmax = 180 nM/mg of protein/min. While NAALA dipeptidase showed a requirement for monovalent anions such as Cl-, the polyvalent anions phosphate and sulfate inhibited enzyme activity 50% at 100 microM and 1 mM, respectively. The divalent metal ion chelators EGTA, EDTA, and o-phenanthroline completely abolished activity, which was partially restored by manganese. Treatment of membranes with 1 mM dithiothreitol abolished NAALA dipeptidase activity. NAALA dipeptidase activity was also sensitive to the aminopeptidase inhibitors bestatin and puromycin, although not to the selective aminopeptidase A inhibitor amastatin. Structure-activity relationships inferred from inhibitor studies suggest that this enzyme shows specificity for N-acetylated alpha-linked acidic dipeptides. NAALA dipeptidase was also potently inhibited by the excitatory amino acid agonist L-quisqualate. Comparison of the properties of NAALA dipeptidase to those of previously characterized enzymes suggests that this is a novel peptidase which may be involved in the synaptic degradation of N-acetyl-L-aspartyl-L-glutamate.[1]

References

 
WikiGenes - Universities