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)

A new enzyme catalyzing the deamidation of seed storage proteins was found in germinating wheat grains and was partially purified. It also acts on egg lysozyme, horse hemoglobin and reduced RNAse, glutamine and Gly-L-Gln-L-Tyr. No activity was observed when using ovalbumin, serum albumin, RNAse, insulin, asparagine and an asparagine-containing peptide. Only glutaminyl residues appear to be deamidated by this enzyme. It differs from transglutaminase and proved to be a true protein deamidase.
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PMID:Protein deamidase from germinating wheat grains. 163 50

The application of high resolution ESR to the investigation of various biological systems is discussed. The advantages of the technique in the study of structural, conformational and dynamic characteristics have been exemplified by spin-labeled human serum albumin, egg lysozyme, liposome membranes, inverted micelles, alpha-chymotrypsin, cotton fiber and cellulose. The polarity of the microenvironment and the mechanism of molecular mobility of the objects under study have been determined. The combination of high resolution and saturation transfer techniques has been shown to give a detailed analysis of very slow molecular motions in biological objects. Peroxide radicals in biosystems have been identified from their ESR spectra at the 2-mm wave band.
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PMID:Investigation of biological systems by high resolution 2-mm wave band ESR. 165 57

The deposition of antigens and immune complexes (IC) in the renal glomerulus is charge-dependent. The demonstration that molecules of net anionic charge, but with discrete positively charged regions, exhibit affinity for the glomerular basement membrane (GBM) extends this concept. Charge hybrid (polar) molecules were constructed by covalently coupling small polycations (lysozyme or linear poly-L-lysine chains with a mean of 17 and 20 residues) to larger polyanions (ovalbumin or human serum albumin (HSA]. Although the products were of overall net anionic charge they still bound to glomerular structures. Immunofluorescence studies performed after i.v. injection of the samples into rats revealed that HSA:poly-L-lysine had the highest affinity. Radioisotopic measurements showed uptake of HSA:poly-L-lysine to be a function of the number of lysine residues; binding of HSA:poly-L-lysine20 was 2.5 times higher than HSA:poly-L-lysine17 (P less than 0.01). Prior injection of a small competing polycation (polyethyleneimine 1200) reduced uptake of HSA:poly-L-lysine by 75%, indicating the charge-based nature of the interaction. HSA:poly-L-lysine20 alone was effectively eliminated from the glomeruli within 72 h. Administration of HSA:poly-L-lysine followed by anti-HSA antibody induced immune complex formation in the capillary wall, giving rise to a granular immunofluorescence pattern and discrete subendothelial and subepithelial deposits. Molecules with polar structure do occur naturally and may contribute to immune complex formation in glomerulonephritis.
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PMID:Surface charge distribution is a determinant of antigen deposition in the renal glomerulus: studies employing 'charge-hybrid' molecules. 174 55

We have mimicked features of immune selection to make human antibodies in bacteria. Diverse libraries of immunoglobulin heavy (VH) and light (V kappa and V lambda) chain variable (V) genes were prepared from peripheral blood lymphocytes (PBLs) of unimmunized donors by polymerase chain reaction (PCR) amplification. Genes encoding single chain Fv fragments were made by randomly combining heavy and light chain V-genes using PCR, and the combinatorial library (greater than 10(7) members) cloned for display on the surface of a phage. Rare phage with "antigen-binding" activities were selected by four rounds of growth and panning with "antigen" (turkey egg-white lysozyme (TEL) or bovine serum albumin) or "hapten" (2-phenyloxazol-5-one (phOx], and the encoding heavy and light chain genes were sequenced. The V-genes were human with some nearly identical to known germ-line V-genes, while others were more heavily mutated. Soluble antibody fragments were prepared and shown to bind specifically to antigen or hapten and with good affinities, Ka (TEL) = 10(7) M-1; Ka (phOx) = 2 x 10(6) M-1. Isolation of higher-affinity fragments may require the use of larger primary libraries or the construction of secondary libraries from the binders. Nevertheless, our results suggest that a single large phage display library can be used to isolate human antibodies against any antigen, by-passing both hybridoma technology and immunization.
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PMID:By-passing immunization. Human antibodies from V-gene libraries displayed on phage. 174 94

The relative susceptibilities of lenticular proteins (alpha, beta and gamma-crystallins) and a number of proteins of non-lenticular origin, to hydroxyl radical-mediated peptide bond cleavage were compared. The non-lenticular proteins (bovine serum albumin, ovalbumin, alcohol dehydrogenase, lysozyme, thyroglobulin, beta-amylase, haemoglobin and carbonic anhydrase) were readily cleaved into acid-soluble fragments following 5 hours treatment with copper ions and hydrogen peroxide. In contrast the crystallins were almost totally unaffected by similar treatment. When alpha-crystallin was pre-treated with acid or cleaved into large fragments with cyanogen bromide it became susceptible to hydroxyl radical attack, yet heating the protein did not diminish its resistance. It is suggested that the resistance of alpha-crystallin to the copper/peroxide-mediated fragmentation may be dependent on the conformation of the protein.
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PMID:Differences in susceptibility between crystallins and non-lenticular proteins to copper and H2O2-mediated peptide bond cleavage. 175 88

IgA specific for 7 food and 6 airborne antigens were sought in the serum of 30 adult patients with IgA mesangial nephropathy (IgA GN), 23 with membranous nephropathy (MGN), 20 with idiopathic nephrotic syndrome (INS), 11 with membranoproliferative GN (MPGN) and 22 healthy controls by means of an enzyme-linked immunoassay. The IgA subclass was determined using monoclonal antibodies. Increased levels of IgA specific for gliadin, bovine serum albumin (BSA), ovalbumin, lysozyme and alpha-lactalbumin were found in IgA GN, while increased levels of IgA to BSA, ovalbumin, lysozyme and alpha-lactalbumin were observed in MGN; IgA specific for alpha-lactalbumin were increased in INS, and MPGN patients had reduced levels of IgA to BSA and increased levels of IgA to beta-lactoglobulin and alpha-lactalbumin. These specific IgA to food antigens were restricted to the IgA1 subclass. Patients with IgA GN had significantly increased levels of IgA specific for Dermatophagoides pteronyssinus (DP) and Dactil while the MGN group showed increased levels of IgA specific for DP, feathers, Dactil and mold. INS patients had increased levels of IgA specific for DP, feathers, Dactil, mold and dog hairs, while MPGN patients had increased levels of IgA specific for feathers, Dactil, dog hairs and mold. All these specific IgA to airborne antigens were restricted to the IgA1 subclass. Patients with the four types of primary glomerulonephritis had decreased IgA specific for cat hairs which were of both the IgA1 and IgA2 subclasses. We conclude that anomalies of the IgA repertoire to environmental antigens are also encountered in primary glomerulonephritis other than IgA GN.
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PMID:Mucosal immunity in primary glomerulonephritis: II. Study of the serum IgA subclass repertoire to food and airborne antigens. 176 94

A guinea pig model of nasal secretory responses was developed to assess the contributions of vascular permeability and glandular secretion responsible for the production of cholinergically stimulated nasal secretions. The nasal secretory responses to provocation with saline, methacholine, and atropine on the ipsilateral (challenged) side and contralateral (reflex) side were analyzed by measurement of total protein (Lowry method), guinea pig albumin (enzyme-linked immunosorbent assay), 125I-labeled bovine serum albumin after intravenous injection, and alkaline phosphatase enzyme activity in nasal fluid. Alkaline phosphatase was found to be localized to submucosal glands by zymography. Topical methacholine challenge increased the secretion of total protein, alkaline phosphatase activity, and albumin on the ipsilateral challenged side, whereas the percentage of total protein represented by albumin was not increased. This response was totally prevented by atropine pretreatment. Serial provocation with methacholine resulted in progressively reduced amounts of both the total protein and alkaline phosphatase in secretions. The observation that repeated challenges produced progressively smaller responses was also examined employing human nasal provocation. Repeating methacholine (25 mg) challenges four times at 10-min intervals in six human volunteers revealed that the initial challenge produced the largest response as reflected in total protein, albumin, lysozyme, lactoferrin, immunoglobulin (Ig) G, IgA, and secretory IgA secretion. When the constituents in secretions were analyzed in relationship to the total protein, the two vascular proteins, IgG and albumin, demonstrated the greatest decrements with repeated methacholine challenges. The glandular proteins, lactoferrin, lysozyme, and secretory IgA, either remained constant or increased in their relative proportion to total protein. Thus, cholinergic stimulation causes glandular secretion from both the guinea pig and human nasal mucosa.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Nasal glandular secretory response to cholinergic stimulation in humans and guinea pigs. 177 47

The intensity of insulin and melittin singly charged molecule ions is suppressed when the sample is mixed with either a lysozyme carrier or bovine serum albumin (BSA) carrier. The suppression with a BSA carrier is shown to be dependent on the carrier concentration. In contrast, luteinizing hormone releasing hormone or glutathione when mixed with insulin or melittin does not result in suppression. These results suggest sample preparation procedures to increase the sensitivity with mass spectrometry.
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PMID:Influence of carrier molecules on the intensity of biomolecule ions in plasma desorption mass spectrometry. 182 26

Studies were conducted to assess the mitogenic effect of lysosomal hydrolases, enzymes known to have an association with allergen- or ozone-induced airway hyperreactivity, on bovine tracheal myocytes in culture. Addition of purified human placental beta-hexosaminidase and partially purified bovine liver beta-glucuronidase resulted in the doubling of cell count after 4 d of incubation in medium M199 with 0.4% FBS. Unstimulated cells remained quiescent without a significant increase of cell count. Lysosomal hydrolases also selectively enhanced 3H-thymidine incorporation four to seven times more than that in vehicle-treated cells or cells treated with endotoxin, a common contaminant of purified enzymes. Ovalbumin (glycoprotein control), pronase, and lysozyme caused a modest but statistically insignificant increase (up to twofold) in 3H-thymidine incorporation. Elastase, collagenase and dialyzed E. coli beta-glucuronidase had no effect. The mitogenic effect of hydrolases was equally seen in quiescent, serum-depleted cells as well as in those maintained in medium with 10% FBS, suggesting that it was independent of serum factors. The effect of lysosomal hydrolases was inhibited by exposure to yeast mannan, and mannosylated human serum albumin had a mitogenic effect, suggesting the involvement of a mannose receptor. We conclude that lysosomal hydrolases may play a role in the development of the hyperplasia/hypertrophy of respiratory smooth muscle.
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PMID:Mitogenic effect of lysosomal hydrolases on bovine tracheal myocytes in culture. 183 69

When assayed in vitro, the activity of the photosynthetic enzyme ribulose 1,5 bisphosphate carboxylase oxygenase is both enhanced and protected from spontaneous decay by exogenous proteins such as hemoglobin, serum albumin, and aldolase. Other proteins and amino acids tested are either ineffective (lysozyme, ferritin, lysine, and cysteine) or afford only partial protection (catalase, glycine, and phenylalanine). Protective proteins do not bind to, or exchange disulfides with, ribulose 1.5 bisphosphate carboxylase/oxygenase. Since their effect can be mimicked by reductively treated detergents such as Triton X-100, it appears that proteins protect from decay by quenching the spontaneous oxidative degradation and inhibiting surface adsorption which could lead to enzyme unfolding. Release of adsorbed molecules from the container surface is likely to be the cause of carboxylase activity enhancement.
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PMID:Protection and enhancement of ribulose 1,5 bisphosphate carboxylase activity by exogenous proteins. 191 Apr 60


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