Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.11 (CD10)
 9,792 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The occurrence of glycosylated proteins in Mycobacterium tuberculosis has been widely reported. However, unequivocal proof for the presence of true glycosylated amino acids within these proteins has not been demonstrated, and such evidence is essential because of the predominance of soluble lipoglycans and glycolipids in all mycobacterial extracts. We have confirmed the presence of several putative glycoproteins in subcellular fractions of M. tuberculosis by reaction with the lectin concanavalin A. One such product, with a molecular mass of 45 kDa, was purified from the culture filtrate. Compositional analysis demonstrated that the protein was rich in proline and that mannose, galactose, glucose, and arabinose together represented about 4% of the total mass. The 45-kDa glycoprotein was subjected to proteolytic digestion with either the Asp-N or the Glu-C endopeptidase or subtilisin, peptides were resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and glycopeptides were identified by reaction with concanavalin A. Peptides were further separated, and when they were analyzed by liquid chromatography-electrospray mass spectrometry for neutral losses of hexoses (162 mass units), four peptides were identified, indicating that these were glycosylated with hexose residues. One peptide, with an average molecular mass of 1,516 atomic mass units (AMU), exhibited a loss of two hexose units. The N-terminal sequence of the 1,516-AMU glycopeptide was determined to be DPEPAPPVP, which was identical to the sequence of the amino terminus of the mature protein, DPEPAP PVPXTA. Furthermore, analysis of the glycopeptide by secondary ion mass spectrometry demonstrated that the complete sequence of the glycopeptide was DPEPAPPVPTTA. From this, it was determined that the 10th amino acid, threonine, was O-glycosidically linked to a disaccharide composed of two hexose residues, probably mannose. This report establishes that true, O-glycosylated proteins exist in mycobacteria.
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PMID:Evidence for glycosylation sites on the 45-kilodalton glycoprotein of Mycobacterium tuberculosis. 762 4

Three different ruminal anaerobic fungi, Neocallimastix frontalis PNK2, Sphaeromonas communis B7, and Piromonas communis B19, were grown axenically or in coculture with Methanobrevibacter smithii on xylan. N. frontalis and S. communis in monoculture and coculture accumulated xylobiose, xylose, and arabinose in the growth medium; arabinose was not metabolized, but xylobiose and xylose were subsequently used. The transient accumulation of xylose was much less evident in cocultures. Both the rate and extent of xylan utilization were increased by coculturing, and metabolite profiles became acetogenic as a result of interspecies hydrogen transfer; more acetate and less lactate were formed, while formate and hydrogen did not accumulate. For each of the three fungi, there were marked increases in the specific activities of extracellular xylanase (up to fivefold), alpha-l-arabinofuranosidase (up to fivefold), and beta-d-xylosidase (up to sevenfold) upon coculturing. The stimulating effect on fungal enzymes from coculturing with M. smithii was independent of the growth substrate, and the magnitude of the stimulation varied according to the enzymes and the incubation time. For an N. frontalis-M. smithii coculture, the positive stimulation was maintained during an extended (18-day) incubation period, and this affected not only hemicellulolytic enzymes but also polysaccharidase and glycoside hydrolase enzymes that were not involved in xylan breakdown. The specific activity of cell-bound endopeptidase was not increased under the coculture conditions used in this study. The higher enzyme activities in cocultures are discussed in relation to catabolite repression.
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PMID:Effect of Methanobrevibacter smithii on Xylanolytic Activity of Anaerobic Ruminal Fungi. 1634 44