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)

Pyridine borane has been reported as a superior reagent over a wide pH range, 5-9, for the reductive methylation of amino groups of proteins with formaldehyde [J. C. Cabacungan , A. I. Ahmed , and R. E. Feeney (1982) Anal. Biochem. 124, 272-278]. It has also been reported to reduce tryptophan to dihydrotryptophan and to inactivate lysozyme in trifluoroacetic acid [M. Kurata , Y. Kikugawa , T. Kuwae , I. Koyama , and T. Takagi (1980) Chem. Pharm . Bull 28, 2274-2275]. In the present study the specificity of pyridine borane for the two different modifications under different reaction conditions has been demonstrated, and extended to the application to the synthesis of protein containing reductively attached carbohydrates. In the acid reduction, pyridine borane selectively reduced all six tryptophans in lysozyme to dihydrotryptophan while all other amino acids remained intact. On similar treatment no cleavage of the carbohydrate moiety from chicken ovomucoid, and no losses of activity of ovomucoid or ribonuclease, two proteins devoid of tryptophan, were observed. Nearly complete methylation of the lysines of lysozyme, chicken ovomucoid, and ribonuclease was achieved with formaldehyde at pH 7.0 after 2 h at room temperature, with the retention of full activity of the protein without any destruction of tryptophan. The same chemistry was applied to covalently attach glucose and lactose to bovine serum albumin. Parameters, including pH, temperature, and methanol, that affect the reactions were investigated. Incremental additions of pyridine borane during the course of the reactions increased the rate of modification. The covalent attachment of sugar to the epsilon-amino group of lysine was demonstrated by the synthesis of N-alpha- acetylglucitollysine and comparison with acid hydrolysates of the bovine serum albumin-sugar derivatives.
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PMID:Pyridine borane as a reducing agent for proteins. 643 Jan 22

The possibility of preservation and restoration of antigenicity of some antigens in paraffin-embedded tissue was evaluated by direct immunofluorescent technique on deparaffinized sections. Fixation with 96% ethanol-1% acetic acid, 10% neutral buffered formalin and p-formaldehyde was useful for the preservation of tissue antigens and immune deposits, whose antigenicity could be easily restored by trypsin digestion. Neutral buffered formalin was also a satisfactory fixative in immunofluorescent staining on lymphocyte/plasma cell-bound immunoglobulins. Fixation with alcohol-Bouin's fluid showed contrast results; feasible for staining of cell-bound immunoglobulins, but poor for that of glomerular immune deposits. After papain digestion, BSA and lysozyme, antigens of immune complexes, were easily detected in experimental chronic serum sickness glomerulonephritis. Pepsin was more efficient than trypsin in restoring the antigenicity of renal tissue antigens such as fibronectin and polyantigenic basement membrane, but the brush border antigen of the proximal renal tubules was frail to the pepsin digestion. In general, the enzymatic digestion time necessary for the restoration of antigenicity was in parallel with fixation time. Results obtained have shown that deparaffinized sections could be used as satisfactory substrate for immunohistochemistry when proper fixation and efficient proteolytic enzymatic pretreatments were performed.
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PMID:Restoration of antigenicity of tissue antigens, cell-bound immunoglobulins and immune deposits in paraffin-embedded tissue. The influence of fixation and proteolytic enzymatic digestion. 643 48

Before attempting to radiolabel proteins it is essential that conditions be found for optimal reaction by use of cold reagents. Iodination by the chloramine-T method was not suitable for radiolabeling of lysozyme as it resulted in reduced solubility, large conformational changes, loss of enzymic activity and a decrease in immunochemical reactivity. On the other hand, reductive methylation of lysozyme by formaldehyde and sodium cyanoborohydride was considered suitable for radiolabeling of lysozyme. The extent of reaction with the free amino groups was dependent on the concentration of lysozyme and the molar ratios of the reactants (lysozyme, NaCNBH3 and HCHO). The molecular weight, net charge and enzymic activity of the lysozyme derivatives were similar to the native molecule. The immunochemical reactivity was reduced by 6-13% when more than 6 amino groups were modified. Reductively methylated rabbit IgG showed unaltered molecular weight, net charge and very little conformational changes compared to native IgG. Partial reaction, by reductive methylation using [14C]HCHO, lysozyme with specific activity of 11.1 X 10(6) cpm/mg protein and pig anti lysozyme antibody with specific activity of 2.95 X 10(5) cpm/mg protein were prepared.
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PMID:Comparative studies on radiolabeling of lysozyme by iodination and reductive methylation. 665 44

A large number of cells containing large eosinophilic granules in their supranuclear cytoplasm was observed in a well differentiated adenocarcinoma of the stomach and its metastases. These cells were identified as Paneth cells by electron microscopy and by their content of lysozyme. Lysozyme-immunoreactivity was well preserved after fixation of tumor tissue in liquid formaldehyde followed by postfixation in osmium tetroxide. Immunoreactivity at immunoelectron microscopy was confined to the large osmiophilic secretory granules. We conclude that morphologically and biochemically differentiated Paneth cells occasionally occur in neoplasms of the gastrointestinal tract.
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PMID:Identification of neoplastic Paneth cells in an adenocarcinoma of the stomach using lysozyme as a marker, and electron microscopy. 699 10

By prolonging the incubation time from 30 min to 20 hr at room temperature, fluorochrome conjugates may be applied at about ten times higher dilution and yet produce specific immunofluorescence staining of enhanced intensity. This modification of the direct method is important for reagent economy and, in addition, affords improved staining features for all antigens tested in formaldehyde-fixed tissues. It is particularly valuable when paired staining is used to characterize lymphoproliferative B-cell processes in pathological routine material; a clear-cut distinction between polyclonal and monoclonal expression of cytoplasmic immunoglobulin (Ig) is obtained, and cells giving rise to a false staining pattern are easily pinpointed. It is likewise advantageous to use prolonged incubation with conjugate for the localization of Ig-producing and Ig-bearing B cells in saline-extracted ethanol-fixed tissues, and the same holds true for Ig and C3 in immune-complex deposits. Also IgE on the surface of mast cells in tissues from atopic subjects is visualized distinctly with this modification. However, the localization or epithelial components is not consistently improved in ethanol-fixed tissues when the incubation time is prolonged; secretory products such as lactoferrin, lysozyme, amylase, and secretory component (SC) are not always immobilized sufficiently by ethanol fixation to avoid diffusion artifacts and a substantial loss from the cytoplasm. Differences in intracellular storage probably contribute to the variable antigen stability.
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PMID:Prolonged incubation time in immunohistochemistry: effects on fluorescence staining of immunoglobulins and epithelial components in ethanol- and formaldehyde-fixed paraffin-embedded tissues. 703 62

Reductive methylation of hen egg-white (HEW) lysozyme with [13C]formaldehyde and NaCNBH3 and subsequent 13C NMR spectroscopy reveal resonances for each of the mono- and dimethyl derivatives of the six lysyl epsilon-amino groups and the NH2 terminus. Each resonance has a unique chemical shift, pKa, and chemical shift change upon deprotonation. The assignment of the resonances arising from the N alpha,N-dimethyl and N alpha-monomethyl NH2 terminus has been made as have resonance assignments for the two lysyl residues which crystallographic studies indicate are involved in ion pair interactions (Imoto, T., Johnson, L. N., North, A. C. T., Phillips, D. C., and Rupley, J. A. (1972) in The Enzymes (Boyer, P. D., ed) 3rd Ed, Vol. 7, pp. 665-868, Academic Press, New York). One resonance, tentatively assigned to the lysine 1 (epsilon NH3+) which forms an ion pair with glutamic acid 7 (gamma COO-), has a highly perturbed chemical shift which shows a biphasic titration curve (N epsilon, N-dimethyl pKa values 10.0 and 2.6). A similar titration curve is observed for a N epsilon-monomethyl lysyl residue. The resonance for lysine 13 (epsilon NH3+), which forms an ion pair with the carboxyl terminus, leucine 129 (alpha COO-), has been assigned by removal of leucine 129 with carboxypeptidase whereupon only one pair of mono- and dimethyl lysyl resonances is greatly perturbed. The pKa of N epsilon,N-dimethyl lysine 13 is 9.3 in des-Arg-Leu-lysozyme in contrast to 9.8 for the intact enzyme. Thus, it appears that both of the intramolecular ion pairs predicted by x-ray crystallography exist in the solution structure of HEW lysozyme.
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PMID:Intramolecular interactions of amino groups in 13C reductively methylated hen egg-white lysozyme. 706 54

Paraffin sections of granulocytic sarcomas (GS) (n = 30) were immunohistochemically evaluated for CD3, CD15 (LeuM1), CD20 (L26), CD31, CD34, CD43, CD45, CD68 (KP1), lysozyme, myeloperoxidase (BM1), CD45RO (UCHL1), and LN5 with an avidin-biotin amplification system and a peroxidase-based color development system with DAB as a chromogen. CD45 positivity was present in all lymphomas and 24 of 25 granulocytic sarcomas. Lysozyme and CD43 labeled 26 of 29 granulocytic sarcomas, showing intense cytoplasmic staining. LN5 (membrane-staining) and CD68 (subtle cytoplasmic caplike staining) were found in 20 of 30 cases, often only focally. BM1 and CD15 mainly labeled maturing granulocytes and mostly were negative in primitive myeloid cells. Myeloid progenitor cell antigens CD31 and CD34 were seen in 7 and 12 of 30 cases, respectively. They seemed to recognize different subsets of myeloid leukemia infiltrates (16 cases positive for at least one); the use of CD31 and CD34 for defining these subsets should be evaluated further. Features suggesting a dual phenotype--T-cell and myeloid (positive for CD3, CD68, and lysozyme)--were documented in two cases. In contrast, lymphoblastic lymphomas (n = 4) were positive for CD3 and CD43 but negative for CD68, lysozyme, CD31, CD34, LN5, and myeloperoxidase. Lymphocytic lymphomas (n = 10) were positive for CD20 and CD43 but negative for all other markers. Small, round-cell tumors (n = 15) were negative for all markers. If T-cell and B-cell differentiation can be excluded with other markers, CD43+ is a sensitive marker for myeloid differentiation. Our results show that several markers are useful in the identification of myeloid leukemia infiltrates and in distinguishing them from lymphoblastic and lymphocytic lymphomas and small round-cell tumors in formaldehyde-fixed, paraffin-embedded tissue.
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PMID:Immunohistochemical evaluation of myeloid leukemia infiltrates (granulocytic sarcomas) in formaldehyde-fixed, paraffin-embedded tissue. 803 68

Monoclonal antibodies (mAbs) have been produced by immunizing BALB/C mice with whole M+ bacteria in incomplete Freund adjuvant and the resulting mAbs for M3 protein have been selected by an indirect immuno-fluorescent technique using formaldehyde-fixed M+ and M- bacteria. Four mAbs reacted with a 65 kDa protein in an extract obtained from the cell wall of M+ bacteria after treatment with N-acetyl muramidase and lysozyme. The purified 65 kDa protein neutralized the phagocytic activity of rabbit anti-M3 antibody. The N-terminal amino acid sequence of the 65 kDa protein was identical with that of protein generated by the M3 gene which has been previously cloned and sequenced. The evidence indicates that the 65 kDa protein is M3 protein. The M3 protein bound not only human fibrinogen but also human serum albumin (HSA). When the M3 protein was purified by gel-filtration and ion-exchange chromatography in the absence of phenylmethyl sulfonyl fluoride (PMSF), four fragments (35 kDa, 32 kDa, 30 kDa, and 25 kDa) in addition to the intact molecule appeared. N-terminal amino acid sequence analysis showed that 35 kDa and 25 kDa fragments were ANAAD and DARSV, respectively, being identical at positions 1-5 and 198-202 to the M3 gene derived protein. Therefore, the 35 kDa and 25 kDa fragments, which were presumed to be cleavage products, may be derived from the C-terminal part and N-terminal part of the intact molecule, respectively. When the effect of purified M3 protein in the bactericidal activity of normal human blood in the presence of M- bacteria was investigated, the M3 protein was responsible for the organism's resistance to attack by phagocytic cells.
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PMID:Purification and characterization of M3 protein expressed on the surface of group A streptococcal type 3 strain C203. 858 Sep 5

Antineutrophil cytoplasmic antibodies (ANCA) are important serological markers for the primary systemic vasculitides, including microscopic polyarteritis and necrotizing crescentic glomerulonephritis. Numerous reports have established the clinical utility of ANCA titer in monitoring disease activity, relapses, and response to treatment. ANCA, detected by indirect immunofluorescence (IIF) assays using patient's serum and ethanol-fixed human neutrophils, produce two common fluorescent staining patterns: cytoplasmic (C-ANCA), involving a 29-kD neutral serine protease termed proteinase 3 (PR3), and perinuclear (P-ANCA), the result mainly of myeloperoxidase (MPO), but occasionally by other components of the azurophilic granules including lysozyme, elastase, cathepsins, and lactoferrin. Some sera contain granulocyte-specific antinuclear antibodies (GS-ANA), which require formaldehyde fixation of neutrophils to cross link cytoplasmic antigens for distinguishing between ANCA and the GS-ANA by IIF. Positive IIF is confirmed by Western blot analysis or specific enzyme-linked immunosorbent assay for PR3, MPO, and other neutrophil granule antigens. The C-ANCA pattern is highly specific for Wegener's granulomatosis, a disease characterized by granulomatous inflammation, necrotizing and crescentic glomerulonephritis, and vasculitis; P-ANCA is found in sera of individuals with vasculitis, glomerulonephritis, and several other diseases. ANCA are predominantly immunoglobulin (Ig)G isotype, but may be IgM and IgA. Various pathophysiologic mechanisms have been proposed involving ANCA-mediated neutrophil activation in a hypothetical model of vasculitic diseases: positive signals via the FcgammaRII (CD32) receptor after IgG-ANCA binding to membrane-associated PR3, relevant cytokines, production of adhesion molecules on both activated neutrophils and endothelial cells, and the release of neutrophil reactive oxygen species and degranulation causing endothelial cell damage. Interference of C-ANCA with PR3 proteolysis and PR3 inhibition physiologically by the alpha1-proteinase inhibitor may have a pathogenic role. No convincing data have been reported for the existence of autoreactive T lymphocytes reactive to any degree with the neutrophil azurophilic enzymes. Studies of various drug- and infectious agent-related diseases and ANCA may contribute to understanding the mechanism(s) involved in some vasculitides.
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PMID:Antineutrophil cytoplasmic antibodies: major autoantigens, pathophysiology, and disease associations. 865 May 85

The exposure to light (20 mW/cm2, an incandescence lamp) of weakly alkaline protein solutions which contained silver nitrate and formaldehyde initiated reduction of silver ions with the subsequent generation of colored silver colloids. At light intensities lower than 0.2 mW/cm2 the generation of colored silver colloids was delayed. The rate of silver reduction depended on the protein type and on the light spectral structure. In particular, solutions which contained prealbumin, lysozyme, gamma-globulin, and transferrin were more photosensitive than solutions which contained albumin, pepsin, and beta-amylase. The formation of [Ag(NH3)2]+ complex after an addition of ammonium ions into the solutions preferentially suppressed silver reduction in the dark and under exposure to red light, thus resulting in a significant difference in the time of appearance of colored silver colloids when the solutions were exposed to violet or red light. These findings are promising for the elaboration of selective silver development of proteins in polyacrylamide gels.
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PMID:Effect of light on generation of colored silver colloids in protein solutions. 963 87


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