Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.5.1.4 (deaminase)
 5,113 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

N-Acetyl-D-[2-3H]glucosamine was synthesized from N-acetyl-D-mannosamine by alkaline 2-epimerization in pyridine containing 3H2O and nickelous acetate. The reaction involves reversible formation of an enol intermediate and therefore also resulted in incorporation of tritium into N-acetylmannosamine. After completed reaction, the two N-acetylhexosamines were separated from other radioactive products and Morgan-Elson chromogens by chromatography on a column of Sephadex G-10, which was eluted with 10% ethanol, and were then separated from each other by chromatography on Sephadex G-15 in 0.27 M sodium borate (pH 7.8). The location of the incorporated tritium was established by treatment of the N-acetylhexosamines with borate under the conditions of the Morgan-Elson reaction, which converts the sugars to Kuhn's chromogen I with concomitant loss of the C-2 hydrogen. As expected, this treatment resulted in the formation of 3H2O, indicating that the tritium was located at C-2. [2-3H]Glucosamine was prepared by acid hydrolysis of the labelled N-acetylglucosamine and was converted to [2-3H]glucosamine 6-phosphate by incubation with hexokinase and ATP. The sugar phosphate was used as a substrate for glucosamine 6-phosphate deaminase (isomerase, EC 5.3.1.10) in a simple 3H2O release assay.
 ...
PMID:Tritium labelling of amino sugars at C-2 by alkaline epimerization in tritiated water. 778 Jan 91

The importance of viridans streptococci as agents of serious extra-oral diseases, including endocarditis, is now recognized. We have tested the hypothesis that the ability to utilize sialic acid as a nutrient source may play a role in the proliferation of these organisms. The type strains of the 15 presently recognized species of viridans streptococci and two clinical isolates-S. oralis (AR3), isolated from a patient with infective endocarditis, and S. intermedius (UNS35), a brain abscess isolate-were studied for their ability to utilize sialic acid. Only S. oralis, S. sanguis, S. gordonii, S. mitis ("oralis group") S. intermedius, S. anginosus, S. constellatus ("milleri group"), and S. defectivus ("nutritionally variant group") were able to use sialic acid (N-acetylneuraminic acid) efficiently as a sole carbon source. Formate, acetate, and ethanol were produced as the major metabolic end-products of sialic acid metabolism, while corresponding glucose-grown cultures produced lactate as the major metabolic end-product. Utilization of sialic acid was independent of the production of sialidase. Cell-free extracts of sialic acid-grown cultures expressed elevated levels of N-acetylneuraminate pyruvate-lyase (NPL; the first enzyme in the intracellular catabolism of sialic acid) and N-acetylglucosamine-6-phosphate (GlcNAc-6-P) deacetylase and glucosamine-6-phosphate (GlcN-6-P) deaminase (enzymes involved in the intracellular catabolism of N-acetylglucosamine). These activities were repressed by growth in the presence of glucose. The intracellular fate of sialic acid, after cleavage by NPL into N-acetylmannosamine (ManNAc) and pyruvate, is uncertain, but the elevated levels of GlcNAc-6-P deacetylase and GlcN-6-P deaminase in sialic acid-grown cells suggest that phosphorylation and isomerization are possible steps in the metabolism of ManNAc to generate an intermediate common to the pathway of N-acetylglucosamine metabolism. The species of viridans streptococci that have the ability to utilize sialic acid are those most commonly associated with extra-oral diseases, and this ability is likely to play a role in the persistence and survival of these infecting organisms in vivo.
 ...
PMID:Utilization of sialic acid by viridans streptococci. 890 24

N-Acetylglucosamine (GlcNAc) and N-acetylneuraminic acid (NANA) are good carbon sources for Escherichia coli K-12, whereas N-acetylmannosamine (ManNAc) is metabolized very slowly. The isolation of regulatory mutations which enhanced utilization of ManNAc allowed us to elucidate the pathway of its degradation. ManNAc is transported by the manXYZ-encoded phosphoenolpyruvate-dependent phosphotransferase system (PTS) transporter producing intracellular ManNAc-6-P. This phosphorylated hexosamine is subsequently converted to GlcNAc-6-P, which is further metabolized by the nagBA-encoded deacetylase and deaminase of the GlcNAc-6-P degradation pathway. Two independent mutations are necessary for good growth on ManNAc. One mutation maps to mlc, and mutations in this gene are known to enhance the expression of manXYZ. The second regulatory mutation was mapped to the nanAT operon, which encodes the NANA transporter and NANA lyase. The combined action of the nanAT gene products converts extracellular NANA to intracellular ManNAc. The second regulatory mutation defines an open reading frame (ORF), called yhcK, as the gene for the repressor of the nan operon (nanR). Mutations in the repressor enhance expression of the nanAT genes and, presumably, three distal, previously unidentified genes, yhcJIH. Expression of just one of these downstream ORFs, yhcJ, is necessary for growth on ManNAc in the presence of an mlc mutation. The yhcJ gene appears to encode a ManNAc-6-P-to-GlcNAc-6-P epimerase (nanE). Another putative gene in the nan operon, yhcI, likely encodes ManNAc kinase (nanK), which should phosphorylate the ManNAc liberated from NANA by the NanA protein. Use of NANA as carbon source by E. coli also requires the nagBA gene products. The existence of a ManNAc kinase and epimerase within the nan operon allows us to propose that the pathways for dissimilation of the three amino sugars GlcNAc, ManNAc, and NANA, all converge at the step of GlcNAc-6-P.
 ...
PMID:Convergent pathways for utilization of the amino sugars N-acetylglucosamine, N-acetylmannosamine, and N-acetylneuraminic acid by Escherichia coli. 986 11