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)

The DD-carboxypeptidase-transpeptidase enzyme system in Streptomyces strain K15 consists of: (1) a membrane-bound transpeptidase capable of performing low DD-carboxypeptidase activity; and (2) a set of DD-carboxypeptidases: (a) membrane-bound, (b) lysozyme-releasable and (c) exocellular, having low transpeptidase activities in aqueous media and at low acceptor concentrations. The DD-carboxypeptidases are related to each other and may belong to the same pathway leading to enzyme excretion. A similar enzyme system occurs in Streptomyces strain R61 except that the membrane-bound DD-carboxypeptidase activity is low when compared with the membrane-bound transpeptidase activity. In Streptomyces rimosus the enzyme system consists almost exclusively of the membrane-bound transpeptidase and the levels of membrane-bound, lysozyme-releasable and exocellular DD-carboxypeptidases are very low.
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PMID:The peptidoglycan crosslinking enzyme system in Streptomyces strains R61, K15 and rimosus. 59 Feb 66

Various biochemical parameters of renal tubular function were examined for a period of up to 12 weeks in rats rendered diabetic by an i.v. injection of streptozotocin. Except for a statistically significant decrease in the urinary excretion of gamma-glutamyl-transpeptidase to 64% of control values, the urinary excretion of beta-N-acetyl-D-glucosaminidase, beta-galactosidase, alanine aminopeptidase, and lactate dehydrogenase significantly increases in diabetic rats to between 154% and 712% of control values. This increased enzymuria is not correlated to the marked polyuria induced by diabetes (r between 0.14 and 0.35, not significant). Enzymuria is also accompanied by a 10-fold increase in the urinary excretion of the low molecular weight protein beta 2-microglobulin while the excretion of albumin is not significantly modified, indicating impairment of tubular reabsorption in diabetic animals. Clearance studies reveal that the clearance of both beta 2-microglobulin and infused egg-white lysozyme are also increased. Finally the histopathologic examination of paraffin sections of the kidney show hydropic degenerescence and pycnosis of the tubular cells. It is concluded that early-stage diabetes results in tubular impairment and that the streptozotocin-rat model appears well suited to the study of these early signs of renal dysfunction.
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PMID:Enzymuria and tubular proteinuria in diabetic rats: a 12-week follow-up study. 134 85

The formation of acceptor for the N epsilon-(D-Ala)-acceptor transpeptidase is an essential feature of nascent peptidoglycan processing. In Gaffkya homari the synthesis of cross-bridges in peptidoglycan includes a variety of penicillin-sensitive enzymes, e.g., transpeptidase, DD-carboxypeptidase, and LD-carboxypeptidase. To determine the primary target, we grew cultures in the presence of the MICs of benzylpenicillin (0.2 microgram/ml), methicillin (10 micrograms/ml), cephalothin (5 micrograms/ml), and cefoxitin (25 micrograms/ml) and examined the monomer-dimer composition of each peptidoglycan by high-performance liquid chromatography after muramidase digestion. From these studies it was recognized that of all the dimers, the synthesis of the predominant cross-bridge, diamidated octapeptide (-Ala-iso-D-Gln-Lys-D-Ala -Ala-iso-D-Gln-Lys-D-Ala), is most sensitive to the action of the beta-lactam at its MIC. The enhanced deamidation of the acceptor tetrapeptide, one of the substrates for the transpeptidase, is correlated with the inhibition of this cross-bridge. For example, at the MIC of benzylpenicillin, the ratio of amidated tetrapeptide to nonamidated tetrapeptide decreased from 2.8 in the control to 1.0 in the treated culture. From these results it would appear that a decrease in preferred acceptor for the transpeptidase results in the inhibition of synthesis of this major cross-bridge. Thus, the metabolism of the amide function of the monomer peptides may represent an additional feature of processing in the assembly of cross-bridged dimers in the peptidoglycan of this organism that is sensitive to the action of beta-lactam.
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PMID:Biosynthesis of peptidoglycan in Gaffkya homari: on the target(s) of benzylpenicillin. 195 43

The peptidoglycan of Staphylococcus aureus contains relatively short glycan chains and is highly cross-linked via its peptide chains. The material from wild-type (strain H) and mutants H28, H4B and MR-1 was freed from the teichoic-acid-linked component and then hydrolysed by Chalaropsis muramidase to yield disaccharide-repeating units of the glycan with attached peptides either non-cross-linked (monomer) or joined to similar units by one (dimer), two (trimer) or more (oligomer) peptide cross links. The resulting fragments were separated by high-resolution HPLC so that distinguishable components as large as nonamer could be identified. Extrapolation showed that, in S. aureus H, H28 and MR-1, oligomers at least as large as eicosamer formed part of the smooth distribution of oligomer fragments, whereas in strain H4B (PBP4-) the maximum size was around dodecamer. The oligomer distribution profile was related to the polymerization theories of Flory, which allow a distinction to be made between a monomer addition model, whereby each oligomer can only be synthesized by the addition of a single monomer unit to its next lower homologue, and a random addition model, in which an oligomer can be formed by linkage of any combination of its constituent smaller units. In S. aureus close approximation to the random addition model for oligomer synthesis and hence for peptidoglycan cross-linking was observed, both in PBP4+ and PBP4- mutants. The implications for secondary cross-linking in S. aureus cell wall formation are inescapable, although the possibility of an endopeptidase/transpeptidase providing later modification of the peptidoglycan is not completely ruled out.
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PMID:Peptidoglycan cross-linking in Staphylococcus aureus. An apparent random polymerisation process. 238 86

Proximal tubular (PT) epithelial cells express MHC class II (Ia) antigens in immunologically-mediated renal injury. To study the role of PT as accessory cells, we generated several murine PT-like epithelial cell lines by transformation with origin-defective SV40 DNA. These transformed cell lines display typical alkaline phosphatase and gamma-glutamyl-transpeptidase enzyme activity, proliferation to epidermal growth factor (EGF) and sodium-dependent glucose uptake. Clonal lines of transformed tubular cells from both normal C3H/FeJ and autoimmune MRL-lpr mice do not constitutively express Ia antigens or mRNA for class II. However, stimulation with recombinant interferon-gamma(rIFN-gamma) induces Ia mRNA and surface product in the cell lines. These Ia-positive cells can process and present hen egg-white lysozyme (HEL) to antigen-specific Iak-restricted T cell hybrids. Unstimulated tubular cells do not express detectable IL-1 alpha, IL-1 beta, TNA-alpha, or IL-6 mRNA. However, stimulation with IL-1 alpha or LPS induces TNF-alpha transcripts. We conclude that these cell lines have characteristics most consistent with a proximal tubular origin. They also bear characteristics of accessory cells such as processing and presentation of antigen and TNF-alpha gene expression. We speculate that PT have the capacity to participate in the pathogenesis of immune renal injury.
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PMID:MHC class II, antigen presentation and tumor necrosis factor in renal tubular epithelial cells. 240 90

The efficacy, renal effects and nephrotoxicity of a short course of treatment with azthreonam were evaluated in 11 adult patients with urinary tract infection. Azthreonam was administered for 5 days at a daily dose adjusted to the residual renal function of the patients. In the pre-treatment period, during treatment and 10 days after completion of therapy, urine cultures, urinalysis and routine renal function tests (clearance of creatinine, urea and uric acid) were performed and urinary enzymes (alanine-aminopeptidase, gamma-glutamyl-transpeptidase, N-acetyl-beta-D-glucosaminidase, lysozyme) were determined. Renal haemodynamics (glomerular filtration rate and effective renal plasma flow) were measured in the pretreatment period and on the 5th day of therapy. The results confirm the efficacy of azthreonam for treatment of urinary tract infection. Results of renal function tests and measurements of urinary enzymes remained unchanged during and after treatment with azthreonam. These data support the conclusion that azthreonam is an effective antimicrobial agent which does not influence renal function or cause nephrotoxic effects.
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PMID:Azthreonam in the treatment of urinary tract infection: evaluation of efficacy, renal effects and nephrotoxicity. 362 45

To verify whether renal tubular dysfunction may account for the CAm/CCr enhancement in acute pancreatitis (AP), we have measured the renal excretion of amylase, lysozyme, and gamma-glutamyl-transpeptidase (GGTP) in 22 patients with AP and in 8 with acute tubular necrosis. While the CAm/CCr ratio was elevated in most patients with AP, the CLys/CCr ratio fell within the normal range in 60% of these patients. The subdivision of patients with AP in subgroups with elevated and normal CLys/CCr ratios revealed a mean CAm/CCr not statistically different. Moreover, no correlation was present in AP between amylase vs. both lysozyme and GGTP clearances. These data suggest that tubular dysfunction does occur in some but not in all the patients with AP and seems not to play a major role in the pathogenesis of the increased CAm/CCr ratio in this condition.
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PMID:Does renal tubular dysfunction account for the enhanced CAm/CCr ratio in acute pancreatitis? 615 8

The peptidoglycan transglycosylase of Bacillus megaterium has been purified approximately 500-fold from a crude membrane fraction. This protein is likely to be the one previously called PG-II and was assayed by its ability to reconstitute with a crude phospho-N-acetyl-muramyl-pentapeptide translocase preparation and partially purified N-acetylglucosaminyl transferase to give peptidoglycan synthesis from nucleotide precursors. The protein was identified as the peptidoglycan transglycosylase by its ability to synthesize lysozyme-sensitive peptidoglycan from undecaprenylpyrophosphoryl-disaccharide-pentapeptide. The enzyme is inhibited by vancomycin but not by bacitracin, penicillin G, or tunicamycin. The enzyme has no detectable transpeptidase activity, but it does bind penicillin.
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PMID:Purification of the peptidoglycan transglycosylase of Bacillus megaterium. 680 46

Streptomyces K15 possesses a set of exocellular and cell-bound D-alanyl-D-alanine carboxypeptidases. Four of them have been isolated to the stage where each enzyme preparation contains on single penicillin-binding protein. The exocellular 54000-Mr enzyme is extremely sensitive to benzylpenicillin and performs low transpeptidase activity on the carbonyl-donor/amino-acceptor tetrapeptide ACLLys(Gly)-DAla-DAla. The exocellular 40 000-Mr enzyme and the two lysozyme-releasable 40 000-Mr and 38 000-Mr enzymes are moderately sensitive to benzylpenicillin and have a high propensity to catalyse dimer formation from the aforementioned tetrapeptide monomer.
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PMID:On the DD-carboxypeptidase enzyme system of Streptomyces strain K15. 723 22

Sortase A (SrtA), originally identified as a transpeptidase in Staphylococcus aureus, plays key roles in full virulence of pathogenic bacteria. In silico genome-wide search suggested a srtA homologue from 05ZYH33, a Chinese human isolate of streptococcal toxic shock syndrome (STSS)-causing Streptococcus suis serotype 2 (S. suis 2, SS2). An isogenic srtA mutant (DeltasrtA) of 05ZYH33 strain was obtained by homologous recombination. Immunofluorescence analysis revealed that two known virulence-associated surface proteins featuring Leu-Pro-X-Thr-Gly motif, muramidase-released protein and surface antigen one, were absent in the DeltasrtA. Piglet infection experiments showed that deletion of srtA attenuated the full virulence of 05ZYH33 strain, and impaired its colonizing potential in specific organs. Furthermore, the DeltasrtA displayed significant reduction in adherence to human cells (Hep-2 and human umbilical vein endothelial cells). Collectively, we concluded that SrtA was involved in the virulence manifestation of STSS-causing SS2.
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PMID:The involvement of sortase A in high virulence of STSS-causing Streptococcus suis serotype 2. 1871 56


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