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)

Stable and metabolically active protoplasts were prepared from the unicellular cyanophyte, Anacystis nidulans, by enzymatic digestion of the cell wall with 0.1% lysozyme. The yield of protoplasts from intact algal cells was approx. 50%. Incorporation of L-[U-14C]leucine into cold trichloroacetic acid-insoluble material from protoplasts preparations was linear for 1.5 h and continued for an additional 2.5 h. Incorporation of radiolabeled leucine into hot trichloroacetic acid-insoluble material from protoplast preparations demonstrated protein synthesis in protoplasts in vitro. Phycocyanin is the principal phycobiliprotein and allophycocyanin is a minor phycobiliprotein in A. nidulans cells. The light-absorbing chromophore of both of these phycobiliproteins is the linear tetrapyrrole (bile pigment), phycocyanobilin. Radiolabeled phycocyanin and allophycocyanin were isolated from protoplast preparations which had been incubated with L-[U-14]leucine or delta-amino[4-14C] levulinic acid (a precursor of phycocyanobilin). The radio-labeled phycobiliproteins were purified by ammonium sulfate fractionation and ion-exchange chromatography on brushite columns. The specific radioactivity of phycocyanin and allophycocyanin in brushite column eluates (protoplasts incubated with radiolabeled leucine) was 106 000 and 82 000 dpm/mg, respectively. The specific radioactivity of phycocyanin and allophycocyanin in brushite column eluates (protoplasts incubated with radiolabeled delta-aminolevulinic acid) was 33 000 and 38 000 dpm/mg, respectively. Phycobiliproteins from protoplasts incubated with radiolabeled leucine were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. 25% of the incorporated radioactivity in protoplast lysates and approx. 60% of the incorporated radioactivity in protoplast lysates and approx. 60% of the incorporated ratioactivity in phycocyanin and allophycocyanin (in brushite column eluates) comigrated with the subunits of these phycobiliproteins on sodium dodecyl sulfate-polyacrylamide gels. Chromic acid degradation of phycobiliproteins from protoplast preparations incubated with delta-amino[4-14C] levulinic acid yielded radiolabeled imides which were derived from the phycocyanobilin chromophore. Imides from radiolabeled phycobiliproteins isolated from protoplast preparations incubated with L-[U-14C]leucine did not contain radioactivity. These results show that both the apoprotein and tetrapyrrolic moieties of phycocyanin and allophycocyanin were synthesized in A. nidulans protoplasts in vitro.
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PMID:Phycobiliprotein synthesis in protoplasts of the unicellular cyanophyte, Anacystis nidulans. 9 57

Mouse lung tumors were induced transplacentally in offspring by treating C3H/HeNCrMTV- and Swiss Webster [Tac:(SW)fBR] mice during different periods of gestation with a single i.p. injection of N-nitrosoethylurea (ENU) at 0.5 mmol or 0.74 mmol/kg. Quantitative and qualitative evaluation of the lung tumors in the offspring at ages ranging from 1 week to 52 weeks was carried out by light microscopic study of hematoxylin and eosin-stained (H&E) serial and step sections. By nitroblue tetrazolium enzyme histochemistry, 3-hydroxybutyrate dehydrogenase (seen predominantly in Clara cells) was localized in frozen tissue sections. By avidin-biotin peroxidase complex immunohistochemistry, various specific cellular and nuclear markers were investigated on paraffin sections (antisera against surfactant apoprotein, Clara cell antigen, lysozyme, and 5-bromo-2' deoxyuridine). Normal lung and lung tumors were also studied by electron microscopy. A histological method was developed to assess all lesions present in the entire lung. It was shown that solid and papillary tumor types arose individually and that mixed solid/papillary forms represented a progression of the benign solid adenoma to the malignant papillary carcinoma. Immunocytochemical localization of DNA synthesis with 5-bromo-2' deoxyuridine gave the highest labeling indices at early stages of tumor growth. As the size of the papillary tumors increased, fewer nuclei were labeled/mm2 of tumor section. Lack of both specific Clara cell antigen and 3-hydroxybutyrate dehydrogenase and the absence of typical nonosmiophilic Clara cell granules indicated a cell of origin other than Clara cells. Evidence for alveolar type II cell origin of both solid and papillary neoplasms in spontaneous and induced tumors was found in the expression of surfactant apoprotein, the presence of mature lamellar bodies (solid tumors) or small lamellar bodies, and immature stages of lamellar bodies (papillary tumors). Lysozyme was present in mature alveolar type II cells and solid tumors but absent in fetal lung and papillary neoplasms. Tumors induced on gestation day 14 or day 16 had all developed by 2 weeks of age and generally did not increase in multiplicity with age, whereas those induced on day 18 showed a protracted development with regard to frequency, growth (size), and progression. The multiplicity of mouse lung tumors induced at different stages of fetal development paralleled the number of alveolar type II precursor cells (i.e., followed a bell-shaped pattern peaking on day 16 of gestation).
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PMID:Origin of spontaneous and transplacentally induced mouse lung tumors from alveolar type II cells. 205 24

We showed previously by using imprint electroimmunofixation that the oligoclonal IgG in sera and CSF from chronic relapsing EAE in guinea pigs were specific to spinal cord and Mycobacterium tuberculosis. We now show that most oligoclonal IgG bands are directed predominantly against isolated myelin basic protein (MBP). Activity to the latter could be removed from sera or CSF by absorption with MBP but not with histone or lysozyme. The oligoclonal IgG reacted weakly with isolated proteolipid apoprotein, and lacked reactivity to myelin-associated glycoprotein. When the oligoclonal IgG activity to myelin proteins was removed from the sera by absorption with a preparation of delipidated myelin before imprint electroimmunofixation, a few bands in some sera still reacted with whole spinal cord homogenate. These results indicate that, in some sera, a part of the oligoclonal IgG was directed against non-myelin proteins or lipids. In contrast to chronic relapsing EAE, CSF oligoclonal IgG from patients with multiple sclerosis showed no reactivity against human brain homogenate, whole myelin, delipidated myelin, and MBP in imprint electroimmunofixation.
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PMID:Specificity of oligoclonal IgG bands against myelin proteins in chronic relapsing EAE in guinea pigs. 243 29

Refolding and disulfide bond formation in reduced denatured bovine alpha-lactalbumin is shown to be Ca2+-dependent. Whereas in the absence of Ca2+ only about 2% of the native active protein is regenerated, in the presence of Ca2+, almost quantitative renaturation is obtained. A close coupling between Ca2+-binding and native disulfide bond formation is also indicated by spontaneous disulfide scrambling in the apoprotein in the presence of low concentrations of thiols. This phenomenon is not found in other disulfide-containing proteins including the homologous chicken lysozyme. It is proposed that the alpha-lactalbumin Ca2+-binding site has the in vivo function of imposing Ca2+ regulation on the folding of nascent alpha-lactalbumin and thereby on lactose synthesis.
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PMID:Calcium regulates folding and disulfide-bond formation in alpha-lactalbumin. 278 42

Lung tissues from 13 patients with pulmonary sclerosing hemangioma were studied with antibody against surfactant apoprotein, Factor VIII-related antigen, or lysozyme. Surfactant apoprotein was detected in the cytoplasm of the cells lining cystic spaces and papillary projections. Surfactant apoprotein was found in a small number of stromal cells with abundant eosinophilic or clear cytoplasm and round to oval nuclei, which were characteristic in pulmonary sclerosing hemangioma as the main component. Surfactant apoprotein was also found in the stromal cells with small, dark nuclei similar to the lining cells. The lining and stromal cells contained neither Factor VIII-related antigen nor lysozyme. Our demonstration of surfactant apoprotein in these cells provides further support for the idea that pulmonary sclerosing hemangioma primarily consists of epithelial cells with differentiation to type II pneumocytes, as was deduced from ultrastructural investigations.
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PMID:Sclerosing hemangioma of the lung. Immunohistochemical characterization of its origin as related to surfactant apoprotein. 298 Nov 38

Regression of hyaline membrane disease was studied with light and electron microscopy, immunohistochemistry using the factor VIII-related antigen, lysozyme, alpha 1-antichymotrypsin and surfactant apoprotein antisera, and biochemical quantitation of surfactant disaturated phosphatidylcholine. The repair of hyaline membrane disease occurred by two processes; expansion of atelectatic alveoli and absorption of the hyaline membrane. Regenerative type II pneumocytes containing numerous organelles and lamellar inclusion bodies could be seen three days following birth. Disaturated phosphatidylcholine content also increased three days after birth. Absorption of the hyaline membrane occurred on part of several types of cells such as intra-alveolar macrophages and spindle-shaped cells appearing below or above the hyaline membrane. Intra-alveolar macrophages showed positive immunoreactivity with lysozyme and alpha 1-antichymotrypsin antisera. The spindle-shaped cells indicated negative immunoreactivity with these antisera, though some of them showed positive immunoreactivity with surfactant apoprotein or factor VIII-related antigen antisera. It thus appears that cells of different origin may possibly participate in the absorption of hyaline membrane.
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PMID:Regenerative process of hyaline membrane disease. Electron microscopic, immunohistochemical, and biochemical study. 313 76

Refolding kinetics of two homologous proteins, lysozyme and alpha-lactalbumin, were studied by following the time-dependent changes in the circular dichroism spectra in the aromatic and the peptide regions. The refolding was initiated by 20-fold dilution of the protein solutions originally unfolded at 6 M guanidine hydrochloride, at pH 1.5 for lysozyme and pH 7.0 for alpha-lactalbumin at 4.5 degrees C. In the aromatic region, almost full changes in ellipticity that were expected from the equilibrium differences in the spectra between the native and unfolded proteins were observed kinetically. The major fast phase of lysozyme folding has a decay time of 15 s. The decay time of alpha-lactalbumin depends on the presence or absence of bound Ca2+: 10 s for the holoprotein and 100 s for the apoprotein. In the peptide region, however, most of the ellipticity changes of the two proteins occur within the dead time (less than 3 s) of the present measurements. This demonstrates existence of an early folding intermediate which is still unfolded when measured by the aromatic bands but has folded secondary structure as measured by the peptide bands. Extrapolation of the ellipticity changes to zero time at various wavelengths gives a spectrum of the folding intermediate. Curve fitting of the peptide spectra to estimate the secondary structure fractions has shown that the two proteins assume a similar structure at an early stage of folding and that the intermediate has a structure similar to that of partially unfolded species produced by heat and, for alpha-lactalbumin, also by acid and a moderate concentration of guanidine hydrochloride.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Comparison of the transient folding intermediates in lysozyme and alpha-lactalbumin. 399 96

12-O-Tetradecanoylphorbol 13-acetate (TPA), phorbol 12,13-diacetate and phorbol 12,13-didecanoate were all potent inducers of thromboplastin activity in human monocytes in vitro, whereas 4 alpha-phorbol 12,13-didecanoate and 4 alpha-phorbol had no such effect. A concomitant increase in titrable apoprotein III antigen was found (apoprotein III is the protein component of thromboplastin). The increase was inhibited by cycloheximide and actinomycin D and partly by alpha-amanitin. The increase of thromboplastin activity was therefore most likely due to synthesis de novo of apoprotein III. The response was approximately halved in the absence of serum or Ca2+. Retinol had a weak inhibitory effect, and retinoic acid was inhibitory only at concentrations that also induced signs of cytotoxicity. TPA caused an initial rise in monocyte cyclic AMP concentration of about 90-120 min duration. No increase in 45Ca2+ influx was induced over 2 h. Good correlation exists between induction of apoprotein III synthesis in monocytes in vitro and mouse skin-tumour promotion in vivo by the various phorbol derivatives. Substances inactive in tumour promotion do not induce the synthesis of apoprotein III. General activating and cytotoxic effects of TPA were monitored by determining release of lysozyme, beta-glucuronidase and lactate dehydrogenase.
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PMID:Phorbol esters induce synthesis of thromboplastin activity in human monocytes. 627 36

Formalin-fixed, paraffin-embedded lungs exhibiting a variety of nonmalignant disorders were studied by immunoperoxidase staining using antibodies specific for surfactant apoprotein, IgG, IgM, IgA, albumin, fibrinogen, and lysozyme. Normal Type II pneumocytes showed staining for surfactant apoprotein in the perinuclear region only. The extent and intensity of staining for apoprotein was markedly increased in reactive Type II pneumocytes. This increase appeared to be a nonspecific reaction to lung injury. The intra-alveolar material in pulmonary alveolar proteinosis stained intensely for surfactant apoprotein, indicating that the accumulated proteinaceous material contained pulmonary surfactant. Type II pneumocytes in pulmonary alveolar proteinosis exhibited hyperplasia as well as hypertrophy. The few macrophages in lung affected by pulmonary alveolar proteinosis stained intensely for lysozyme. The excessive intraalveolar accumulation of proteinaceous material in pulmonary alveolar proteinosis may be the result of both an over-production as well as a deficient removal of pulmonary surfactant.
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PMID:Surfactant apoprotein in nonmalignant pulmonary disorders. 700 1

This study investigated the intracellular distribution of lysozyme, a protein that is synthesized and secreted by rat alveolar type II epithelial (ATII) cells and alveolar macrophages, using a polyclonal antibody generated against purified rat lysozyme. Lysozyme was immunoprecipitated with this antibody from Triton X-100 lysates of ATII cells cultured on a basement membrane derived from Englebreth-Holme-Swarm mouse sarcoma (EHS) and radiolabeled with 35S-methionine. ATII cells cultured on EHS basement membrane for several days were fixed and labeled with antibodies to surfactant apoprotein A (SP-A) and lgp-120 (a lysosomal glycoprotein), or lysozyme and lgp-120, and studied by confocal microscopy. Organelles were identified that stained positively for either anti-lysozyme or anti-lgp-120; a second population of organelles contained both markers. Similarly, two populations of SP-A-containing organelles were identified; one contained the lysosomal glycoprotein lgp-120. In addition, confocal images demonstrated that both SP-A and lysozyme were secreted by ATII cells, as evidenced by the accumulation of secretory products within the lumen of the cyst-like aggregates. When the subcellular localization of SP-A and lysozyme was studied by analytical cell fractionation, two populations of organelles were identified that contained SP-A or lysozyme. The lighter population accounted for approximately 32% of SP-A and 33% of total intracellular lysozyme and was recovered in the same region of the gradient as secretory lamellar bodies. The more dense population co-localized with lysosomes and accounted for approximately 67% of both SP-A and lysozyme recovered. Western blots of cell fractions revealed intact lysozyme in all the cell fractions. The results of these experiments suggest that lysozyme has a similar intracellular distribution as surfactant apoprotein A in ATII cells. Lysozyme is found in fractions containing lamellar bodies where it is packaged for secretion, and in lysosomal fractions where it may undergo degradation.
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PMID:Intracellular distribution of lysozyme in rat alveolar type II epithelial cells. 788 8


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