Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous findings have demonstrated the presence of muramic acid and the lack of sialic acid in gastropod glycoconjugates from different tissues. The present study investigated the composition of muramyl derivatives in Mollusca Gastropoda tissue from the foot, mantle and periesophageal ganglia, using HRP-labeled lectins (LTA, UEA I, GSA IB4, GSA II, DBA, SBA, RCA II, WGA, PNA, ConA) and glycosidase digestion (neuraminidase, lysozyme, alpha-L-fucosidase, beta-N-acetylglucosaminidase, alpha-N-acetylgalactosaminidase). Muramyl derivatives from the tissue examined showed some differences related to the composition of the terminal disaccharides. Indeed, foot and mantle mucocytes exhibited muramic acid in a terminal position, linked to (subterminal) N-acetylgalactosamine, whereas in neuron cells muramic acid was present in an internal position and linked to N-acetylglucosamine. Diversities also occurred between foot and mantle mucocytes with respect to the receptor sugar for penultimate N-acetylgalactosamine.
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PMID:Identification of muramyl derivatives in Mollusca Gastropoda tissue. 191 77

Three possible modes of recognition of human lactoferrin (Lf), which is avidly taken up by the mouse liver, were examined. First, Lf has terminal galactosyl residues for which a receptor exists on hepatocytes. However, when large amounts of Lf were injected with 125I-asialoorosomucoid, no inhibition of asialoorosomucoid uptake by the liver was observed. Second, Lf that exposes fucosyl residues could be recognized by the sugar-polyspecific receptor of liver sinusoidal cells. Digestion of Lf by fucosidase did not affect considerably the uptake of Lf. In addition, bovine Lf, which lacks fucosyl residues, was also avidly taken up by the liver, and this uptake was inhibited by human Lf. Mannan and horseradish peroxidase, which are recognized by the sugar-polyspecific receptor, did not inhibit Lf uptake. These data demonstrate that galactosyl and fucosyl residues are not essential for Lf recognition. Third, Lf could be recognized by its protein moiety. To investigate this possibility, we used two Lf derivatives with intact carbohydrate side chains, carbamylated Lf and the C-terminal half molecule of Lf. Carbamylation reduced the uptake of Lf and its competitive activity toward the uptake of 125I-Lf. The C-terminal fragment, like carbamylated Lf, had a much weaker competitive activity than intact Lf. Therefore, the integrity of the protein moiety of Lf was required for its effective uptake by the liver. As Lf is a cationic protein, competition experiments were also done with lysozyme, another cationic protein which in the form of dimer is taken up by the liver reticuloendothelial system. The strong inhibition by dimerized lysozyme suggests that the liver reticuloendothelial system has common binding sites for certain cationic proteins, as recently shown for isolated macrophages.
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PMID:Uptake of lactoferrin by the liver. III. Critical role of the protein moiety. 632 58

We prospectively evaluated concentrations of beta-D-galactosidase, alpha-L-fucosidase, beta-D-N-acetylglucosaminidase, and lysozyme in urine from normal subjects, ambulatory patients with cystic fibrosis (CF), and CF patients with previously normal renal function who were receiving intravenous aminoglycoside (AG) therapy. Enzyme activities were generally low or negligible in subjects not receiving AG. Enzymuria was documented during 12 of 13 AG treatment courses and most frequently involved beta-D-N-acetylglucosaminidase excretion. In nine courses, enzymuria occurred in the absence of proteinuria or elevations of blood urea nitrogen and serum creatinine. In three courses attended by enzymuria and evidence of nephrotoxicity, neither the time of appearance nor the magnitude of enzymuria was different from that of nonnephrotoxic patients. In two of these three treatment courses, enzymuria preceded clinical evidence of nephrotoxicity of 16 and 5 days, and in the third course enzymuria and elevation of blood urea nitrogen and serum creatinine occurred simultaneously. We conclude that enzymuria is not a reliable predictor of nephrotoxicity due to AG in CF patients and is not an indication of discontinue AG therapy.
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PMID:Are measurements of urine enzymes useful during aminoglycoside therapy? 679 92

Lysosomal acid hydrolases were surveyed in elicited and non-elicited rat peritoneal macrophages to determine the types of enzymes present and optimal assay conditions. Adherent peritoneal cells (primarily macrophages) were cultured 24 hours prior to use. Intracellular distribution of enzymes was determined by differential centrifugation of whole cell homogenates into nuclear, cytoplasmic, and lysosomal fractions. The acid glycosidase, acid phosphatase, acid protease, and lysozyme were largely sedimentable in the lysosomal fraction. Much enzyme activity was latent, being activated by addition of Triton X-100. Chymotrypsin-like protease activity in cell fractions was apparently due to low level mast cell contamination. Elicited macrophages had elevated total cell protein as compared to non-elicited cells, but changes in intracellular enzyme levels were selective depending on the enzyme and the stimulus used to elicit macrophages. Thioglycollate-elicited cells showed elevations of most acid hydrolases compared to non-elicited cells, whereas enzyme levels in zymosan-elicited cells were similar to those in non-elicited cells. All elicited cells showed marked decreases in total cellular alpha-D-mannosidase and alpha-L-fucosidase compared to non-elicited cells. Intracellular lysozyme levels also varied between different rat strains. Cultured macrophages exhibited increasing intracellular levels and extracellular secretion of acid hydrolases, especially extracellular lysozyme (10-25 mug/10(6) cells/day), over 72 hours. No significant intra- or extracellular elastinolytic activity was detected.
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PMID:Selective modification of rat peritoneal macrophage lysosomal hydrolases by inflammatory stimuli. 710 74

Lysosomes and lysosomal enzymes are known to be involved in cancer processes. However, integrated biochemical and cell biology studies are necessary to understand how lysosomal enzymes could initiate cancer. Most breast cancer is initiated in the milk ducts. The hypothesis presented here is that lysosomal enzymes are exocytosed into the milk ducts where these hydrolytic enzymes damage cells leading to the initiation of cancer. Lysosomal enzymes include: many cathepsins, acid phosphatases, DNAases, ribonucleases, sulfatases, glucuronidase, lipases, neuramidase, lysozyme, fucosidase, phosphodiesterases, glucosidases, galactosidases, mannosidase, and glucosaminidase. Risk factors for breast cancer that could initiate activity of lysosomal enzymes include: ionizing radiation, oxidative stress, estrogen, environmental toxicants and dietary components. Measurements of multiple lysosomal enzyme activities and their biochemical pathways are vital to the understanding of protectors to inhibit lysosomal enzyme activities that might be leading to breast cancer. Non-invasive screening assays could be developed to measure in vivo milk duct lysosomal enzyme activities. Lysosomal enzyme activities may be precursors to the onset of other kinds of cancer with other similar non-invasive screening techniques possible.
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PMID:Lysosomal enzymes and initiation of breast cancer. 1560 57