Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Recent studies by DNA-DNA hybridization revealed that strains now designated as L. acidophilus, can be divided into several groups and only one group should be classified as L. acidophilus. We studied several phenotypic characteristics in representative strains from the six DNA-homology groups of L. acidophilus. No group specific pattern was observed among the strains for fermentation of eight carbohydrates, growth at 15 and 45 degrees C, resistance to 0.2% oxgall, lysis by lysozyme or sensitivity to 17 antibiotics. However, some differences among groups were observed in beta-galactosidase (beta-gal) activity and surface layer (s-layer) protein. Strains in B1 do not have a s-layer or beta-gal while B2 strains also lack a s-layer but do possess beta-gal. All strains in groups A1, A2, A3 and A4, capable of growing in lactose, have beta-gal activity and also have a s-layer composed of protein subunits of different molecular weights (MW). Strains in A1 homology group have a s-layer with 46 Kd protein subunits while strains in other A groups have s-layer protein subunits that varied in MW within each group. On the basis of these two traits several isolates of unknown homology groups have been tentatively placed in A1, B1 or B2 groups. L. acidophilus from A1 group showed strain variation in beta-gal specific activity and rate of acid production and growth. For use in dietary adjuncts, L. acidophilus strains should be selected for these three and other desirable traits. They should be maintained and grown in media containing lactose.
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PMID:Selection of Lactobacillus acidophilus strains for use in "acidophilus products". 311 4

Developing and healing inflammatory lesions were topically produced in the skin of rabbits by sulfur mustard (SM). After the rabbits were sacrificed, the various lesions were removed and organ-cultured. The organ-culture fluids extracted the extracellular lysosomal enzymes (acid phosphatase, beta-glucuronidase, beta-galactosidase, and lysozyme), so that they could be measured biochemically along with lactic dehydrogenase (LDH), an enzyme marker for cell death. In tissue sections, the number and types of cells were counted, and their lysosomal enzyme content evaluated histochemically. The culture fluids from peak lesions contained much lower levels of all five enzymes than did culture fluids from healing lesions. When histological-histochemical-biochemical correlations were made, serum, macrophages (MN), and activated fibroblasts (but not tissue PMN) appeared to be major sources of extracellular lysosomal enzymes in peak lesions; and the dead PMN in the crusts and the activated fibroblasts in the tissues appeared to be major sources in healing lesions. The high lysosomal enzyme content of the crusts covering the lesions suggests that this passive barrier may also play an active role in promoting healing and in protecting against invasion by microorganisms.
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PMID:Sources of extracellular lysosomal enzymes released in organ-culture by developing and healing inflammatory lesions. 342 85

Stable activated macrophage hybridomas were generated by somatic cell fusion between Propionibacterium acnes-induced peritoneal exudate cells and NS-1 myeloma cells. Five cell lines were obtained and each was cloned by limiting dilution; 59 clones were obtained. The cells of 2 clones (MP4-4 and MP4-8) which adhered to the culture dishes were selected for further analysis. These hybridomas exhibited non-specific esterase and beta-galactosidase intracellularly, and asialo GM1, Mac-1, Ia antigens and Fc-receptors on their cell surface. They did not, however, show phagocytic activity or secrete lysozyme. These hybridomas (MP4-4 and MP4-8) secreted the cytotoxic factor without any stimulation. Furthermore strong cytotoxic activity was found in ascites and sera from nude mice inoculated with these hybridomas. These activated macrophage hybridomas should be very useful in studies on cancer immunology and the physiology of macrophages.
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PMID:Activated macrophage hybridomas secreting a cytotoxic factor. 380 45

The interaction of complement and polymyxin with gram-negative bacteria has been investigated by using three strains of Salmonella typhimurium in an attempt to determine the loci of complement action. It has been shown that the bactericidal activities of complement and polymyxin towards a smooth gram-negative organism are similarly affected by various components of the bactericidal test system. Further, complement and polymyxin have been shown to act synergistically in the bactericidal event. Evidence is presented which suggests that each agent produces lesions in the outer membrane of gram-negative bacteria, allowing lysozyme to interact with its glycopeptide substrate. An attack on the inner cytoplasmic membrane follows, since cell respiration is rapidly inhibited and this membrane becomes sufficiently disorganized to permit massive leakage of beta-galactosidase from the cytoplasm of the target cells.
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PMID:Interaction of complement and polymyxin with gram-negative bacteria. 434 65

Pure cultures of three types of mononuclear phagocytes-mouse peritoneal macrophages, unstimulated or after thioglycollate stimulation, and human monocytes-synthesize and secrete large amounts of lysozyme in vitro. The macrophage lysozyme is indistinguishable from authentic lysozyme in its ability to lyse M. lysodeikticus, inhibition by specific antisera, a similar size of 14,000 and cationic charge. Lysozyme secretion in culture is characterized by a large net increase in total lysozyme, 4-20-fold in 3 h, 75-95% of which is in the medium, and its continued extracellular accumulation over at least 2 wk in culture. Lysozyme is the major (14)C-labeled protein secreted into the medium by both unstimulated and thioglycollate-stimulated macrophages and the 0.75-1 microg produced per 1 x 10(6) cells/day represents 0.5-2.5% of the total cell protein. Lysozyme is a cell-specific marker for mononuclear phagocytes and the PMN, which contains preformed enzyme, since it is absent in lymphoid cells and a variety of fibroblast and epithelioid cell lines. Lysozyme production is also a useful measure of mononuclear phagocyte cell number. The rate of lysozyme production and secretion is remarkably constant for all cell types under a variety of culture conditions. Production by the mouse macrophage increases threefold on the 2nd day in culture and then remains linear with time. Production is optimal at a relatively low serum concentration, but can be maintained, in the absence of serum, in lactalbumin hydrolysate or, at a reduced level in basal media. The production and secretion of lysozyme are independent of the production of macrophage acid hydrolases. Net increase and secretion of lysozyme occur under conditions where acid hydrolases like N-acetyl beta-glucosaminidase, beta-glucuronidase, beta-galactosidase, and cathepsin D are neither accumulated nor secreted. Massive phagocytosis of latex particles has no effect on lysozyme production and secretion. Lysozyme production can be rapidly inhibited by treatment with cycloheximide (0.4 microg/ml) whereas inhibition of its production by colchicine (10(-6) M) occurs only after a lag period of more than 8 h, and is probably due to a secondary effect. These results show that mouse macrophages provide a simple in vitro system to measure lysozyme secretion and its control. These studies also indicate the possible importance of mononuclear phagocytes in the secretion of a variety of biologically active products and in the modification of their environment.
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PMID:In vitro synthesis and secretion of lysozyme by mononuclear phagocytes. 482 44

Hypertonic sucrose inhibited the bactericidal activity of lysozyme-free serum against a rough strain of Escherichia coli. The duration of the inhibition correlated with the duration of plasmolysis caused by the sucrose. Although the lethal action of the serum was delayed, the prompt release of alkaline phosphatase by the cells suggested that nonlethal damage to the cell wall had taken place under these conditions. In contrast, the crypticity of the cells for beta-galactosidase did not deteriorate until the viability of the bacteria began to decrease. It is concluded that the primary site of action of serum is at the bacterial cell wall; however, in the absence of lysozyme, the lethal event was subsequent damage to the bacterial cell membrane.
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PMID:Locus of the lethal event in the serum bactericidal reaction. 488 4

Four proteins, which have been designated A, B, C and D, have been purified from human parotid saliva. These proteins are the major constituents of parotid saliva which migrate rapidly to the anode in polyacrylamide electrophoresis at pH9.5. Gel filtration and polyacrylamide electrophoresis were employed in the purification procedures. After purification all four preparations were tested for homogeneity by electrophoresis at pH2.8 and 9.5, by isoelectric focusing in the pH range 3-10, by immunodiffusion, and by sedimentation in the analytical ultracentrifuge. None of the proteins showed significant activity in assays for amylase, acid and alkaline phosphatase, protease, lysozyme, ribonuclease, peroxidase, beta-glucuronidase, beta-galactosidase, iron-binding activity and esterase. No cross-reactions were detected with antisera specific for lactoferrin and 15 serum proteins. All four proteins were rich in glutamic acid, proline and glycine and were lacking completely the sulphur-containing amino acids. Proteins A and C contained no threonine or tyrosine. Carbohydrate could be demonstrated only in protein A at a concentration of 4% of the total protein.
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PMID:Purification and partial characterization of four proteins from human parotid saliva. 500 93

Extracts of Acanthamoeba castellanii (Neff) contain alpha- and beta-glucosidase, beta-galactosidase, beta-N-acetylglucosaminidase, amylase, and peptidase. All of these activities are optimal between pH 3 and 4. These extracts also were found to clarify suspensions of cell walls from nine different gram-positive bacteria, including Micrococcus lysodeikticus. The pH optimum for the lytic activity was between 3 and 4. The extent of lysis of the various cell walls did not correlate with the release of free amino groups and of free N-acetylated sugars from the walls during digestion with these extracts. Suspensions of cell walls of Escherichia coli (a gram-negative bacterium), Cordiceps militaris (a fungus), and Acanthamoeba cysts, as well as of colloidal chitin, were not clarified by incubation with these extracts, although reducing sugars were released from each of these materials. Exhaustive digestion of M. lysodeikticus walls by lysozyme released no free N-acetylglucosamine. The products of exhaustive digestion of this cell wall with Acanthamoeba extracts were free N-acetylglucosamine, free N-acetylmuramic acid, glycine, alanine, glutamic acid, lysine, and N-acetylmuramic acid peptide fragments. These results suggest that the amoeba extracts contain endo- and exo-hexosaminidases, in addition to beta-hexosaminidase and peptide hydrolases.
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PMID:Effect of lytic enzymes of Acanthamoeba castellanii on bacterial cell walls. 578 74

A plasmid-encoded enzyme reported by us to phosphorylate amikacin in a laboratory strain of Escherichia coli has been localized in the bacterial cell. More than 88% of this amikacin phosphotransferase (APH) activity was retained in spheroplasts formed by ethylenediaminetetraacetate-lysozyme treatment of an APH-containing E. coli transconguant known to form spheroplasts readily. By comparison, the spheroplasts retained 94% of deoxyribonucleic acid polymerase I and 98% of glutamyl-transfer ribonucleic acid synthetase, two internal markers, whereas less than 10% of the activity of a periplasmic marker, acid phosphatase, was present in spheroplasts. Treatment of whole cells of the transconjugant with chemical probes incapable of crossing the plasma membrane obliterated acid phosphatase activity, whereas the internal markers deoxyribonucleic acid polymerase I, glutamyl-transfer ribonucleic acid synthetase, and beta-galactosidase were virtually unaffected after treatment for 5 min; more than 60% of the APH activity remained. As a control, similar chemical treatment of sonic extracts, in which enzymes were not protected by bacterial compartmentalization, produced more extensive reduction in the activities of all test enzymes, including APH. Spheroplasts preincubated with adenosine triphosphatase were shown by thin-layer chromatography to phosphorylate amikacin. Spheroplasts of cells grown in the presence of H(3) (32)PO(4) were shown to utilize internally generated adenosine 5'-triphosphate in the phosphorylation of amikacin. The absence of (32)P-phosphorylated amikacin after incubation of [gamma-(32)P]adenosine 5'-triphosphate with spheroplasts confirmed that exogenous adenosine 5'-triphosphate was not used in the reaction. These results suggest an internal location for APH. This conclusion has implications for the role of such enzymes in aminoglycoside resistance of gram-negative bacteria.
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PMID:Localization of an amikacin 3'-phosphotransferase in Escherichia coli. 626 7

Aging is assumed to decrease lysosomal enzyme release from polymorphonuclear leukocytes (PMN). A synthetic chemotactic peptide, N-formyl-methionyl-leucyl-phenylalanine (fMet-Leu-Phe) was utilized to stimulate enzyme release of PMN from 45 human subjects, 21 males and 24 females, ranging in age from 22-83 yr old. Results of the studies showed no sex differences in the stimulation of enzyme release for either age group. However, stimulation was found to significantly decline in both males and females over 50 yr old compared to subjects under 50 yr old. The linear formulae for beta-glucuronidase, beta-galactosidase and lysozyme in male subjects were Y = 6.5X + 617.2, Y = -1.9X + 311.5 and Y = -1.9X + 327.3 with correlation coefficient of -0.685, -0.352 and -0.401, respectively. The linear formulae in females were Y = -5.2X + 536.6, Y = -3.0X + 340.6 and Y = -1.7X + 333.6 with correlation coefficient of -0.582, -0.303 and -0.462, respectively. These findings suggest that there was an age-related decline of response to the stimulant, fMet-Leu-Phe.
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PMID:Age-related decline in lysosomal enzyme release from polymorphonuclear leukocytes after N-formyl-methionyl-leucyl-phenylalanine stimulation. 642 Jan 76


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