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

---

Query: EC:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The complete covalent structure of Protein A, a protein degraded during bacterial spore germination, has been determined. The intact protein was cleaved with a highly specific spore protease into two peptides, residues 1 to 21 and 22 to 61. The larger peptide was further cleaved into two fragments with either cyanogen bromide or by trypsin cleavage following arginine modification with cyclohexanedione. The peptides derived from cyanogen bromide fragmentation encompassed residues 22 to 53 and 54 to 61 while trypsin hydrolysis yielded overlapping fragments comprising residues 22 to 48 and 49 to 61. Automated sequenator analysis together with carboxypeptidase Y digestion of the intact protein and the peptide fragments provided data from which the following unique amino acid sequence was deduced. NH2-Ala-Asn-Thr-Asn-Lys-Leu-Val-Ala-Pro-Gly10-Ser-Ala-Ala-Ala-Ile-Asp-Gln-Met-Lys-Tyr20-Glu-Ile-Ala-Ser-Glu-Phe-Gly-Val-Asn-Leu30-Gly-Pro-Glu-Ala-Thr-Ala-Arg-Ala-Asn-Gly40-Ser-Val-Gly-Gly-Glu-Ile-Thr-Lys-Arg-Leu50-Val-Gln-Met-Ala-Glu-Gln-Gln-Leu-Gly-Gly60-Lys-COOH.
...
PMID:Covalent structure of protein A. A low molecular weight protein degraded during germination of Bacillus megaterium spores. 11 74

The binding of Ca2+ to a previously described phosphoprotein from human parotid saliva, protein A [Bennick (1975) Biochem J. 145, 557-567] was studied by means of equilibrium dialysis. In 5 mM-Tris/HC1 buffer, pH7.5, protein A bound 664nmol of Ca/mg of protein. Km was determined to be 181 muM and the binding of Ca2+ to the protein was non-co-operative. The binding of Ca2+ apparently occurs to side-chain carboxyl groups in the protein, but protein phosphate is of minor if any importance in calcium binding. Hydrolysis of protein A by trypsin and collagenase or heating of the protein at 60 degrees or 100 degrees C did not affect Ca2+ binding. The Ca2+ binding decreases with increased concentration of the dialysis buffer and on the addition of SrCl2, or MgCl2 or MnCl2 to the dialysis buffer. Protein A does not aggregate in the presence of Ca2+, since the s20,w was identical when determined in the presence (1.30S) and absence (1.35S) of CaCl2. By use of a specific antiserum to protein A it was found that protein C [Bennick & Connell (1971) Biochem. J. 123, 455-464] and perhaps minor related components cross-reacted with protein A. No other salivary proteins showed immunological similarity. Proteins A and C were also present in submandibular saliva. The possible functions of protein A are discussed.
...
PMID:The binding of calcium to a salivary phosphoprotein, protein A, common to human parotid and submandibular secretions. 18 Sep 80

Protein A and C, which are major components of the acidic proline-rich proteins in human saliva, were digested, before or after adsorption to hydroxyapatite, with alkaline phosphatase, trypsin, thermolysin and a proteinase preparation from salivary sediment. The results demonstrate that the binding site is located in the proline-poor N-terminal part of the protein, possibly between residues 3 and 25. Phosphoserine is necessary for maximal adsorption of the proteins to hydroxyapatite. When proteins A and C are adsorbed to hydroxyapatite before proteolytic digestion there is a protection of some of the susceptible bonds in the N-terminal part of the proteins and a gradual removal of the proline-rich C-terminal part. Thermolysin can cleave susceptible bonds in the part of the protein that remains bound to hydroxyapatite, but at least some of the resulting peptides are retained on the mineral. Since the ability of the proteins to inhibit hydroxyapatite formation and to bind calcium is located in the N-terminal proline-poor part, it is possible that these activities are retained after proteolytic digestion of the adsorbed proteins.
...
PMID:The nature of the hydroxyapatite-binding site in salivary acidic proline-rich proteins. 23 Aug 18

Polyclonal antibodies were raised in rabbits towards reduced subunits of human cervical mucus glycoproteins. The reduced subunits almost completely inhibited the antiserum, whereas the intact mucins and the heavily glycosylated fragments obtained after digestion of reduced subunits with trypsin (T-domains) caused only partial inhibition. Periodate oxidation of intact mucins, reduced subunits and T-domains caused no effect on the antibody response, and fragments obtained by more extensive proteolysis of the reduced subunits (P-domains) showed no inhibitory activity. By using electron microscopy, antibodies from T-domain-adsorbed antisera were revealed as bound to cervical mucin reduced subunits, either directly or with colloidal gold-Protein A. Binding sites (100-150 nm apart) were observed at the ends and at internal positions of the reduced subunits. We conclude that the antibodies do not recognize carbohydrate structures but are directed to two kinds of protein epitopes, one shared by whole mucins, reduced subunits and T-domains, and the other specific to the reduced subunit fragment. The latter epitopes are 'cryptic' and are probably shielded within folded protein domains stabilized by disulphide bonds. Human bronchial, cervical, gastric and salivary mucus glycoproteins share some of these cryptic epitopes.
...
PMID:Evidence for shared epitopes within the 'naked' protein domains of human mucus glycoproteins. A study performed by using polyclonal antibodies and electron microscopy. 170 99

Skin lesions associated with alpha 1-antitrypsin deficiency are becoming better defined and understood. Deficiency in this major antiproteinase, which neutralizes multiple proteolytic enzymes ranging from collagenases and elastases to trypsin and chymotrypsin, thus results in significant tissue autodigestion. This anti-proteinase is secreted by activated lymphocytes and macrophages, suggesting the existence of homeostasis which titrates the release of proteolytic enzymes by these cells, and the adequate neutralization of these proteases in order to prevent excessive tissue autodigestion each time these inflammatory cells are activated. We report a patient with alpha 1-antitrypsin deficiency who, following insect bites and cellulitis developed widespread itching and scratching, leading to widespread lesions of prurigo nodularis. The colonization of his multiple skin lesions with Staphylococcus aureus and the release of potent T cell mitogens, such as Protein A and enterotoxin A from the bacterial cell membrane may have resulted in the release of additional proteolytic enzymes by the activated lymphocytes and macrophages, without the concomitant secretion of alpha 1-antitrypsin with subsequent aggravation of his pruritus. These concepts are supported by electron microscopic evidence of excessive tissue autodigestion, and by immunocytochemical data identifying the presence of T helper and T cytotoxic/suppressor lymphocytes as well as macrophages within the upper dermis.
...
PMID:Alpha-1 antitrypsin deficiency in a patient with widespread prurigo nodularis. 182 11

Bacterial adherence to surfaces is the determining first step in staphylococcal infections. Activated platelets mediate adherence of staphylococci to tissues during inflammation or infection; however, the molecular mechanisms of this interaction are not clearly understood. Thrombospondin, a large multifunctional glycoprotein, is the principal platelet-stored glycoprotein. It is secreted upon platelet activation and either bound to receptors on the platelet surface or released and incorporated into blood clots and extracellular matrices. To characterize thrombospondin binding to staphylococci, we incubated [125I]thrombospondin with Staphylococcus aureus Cowan 1 in the presence of albumin and separated bound and free thrombospondin by centrifugation. We found that binding was (i) specific, since it was up to 76% inhibitable and up to 60% reversible in the presence of a 100-fold excess of unlabeled thrombospondin, (ii) saturable, with an apparent dissociation constant (Kd) of 5.6 x 10(-9) M and a maximal number of 2,600 binding sites per microorganism, and (iii) Ca2+ dependent, since omission of this ion from the medium decreased significantly the binding capacity. The binding reaction was insensitive to previous trypsin treatment of bacteria, but it was strongly inhibited in the presence of heparin. Protein A-negative and -positive strains had similar binding characteristics. To determine the promotion of staphylococcal adherence to surfaces by solid-phase thrombospondin, we incubated 3H-labeled S. aureus Cowan 1 and 26 pathogenic staphylococcal isolates with thrombospondin-coated polymethylmethacrylate disks and found that adherence was significantly promoted as a function of adsorbed thrombospondin. These results indicate a role for thrombospondin as an important mediator of staphylococcal adherence to activated platelets, to blood clots, or to extracellular matrices in pyogenic infections.
...
PMID:Thrombospondin binds to Staphylococcus aureus and promotes staphylococcal adherence to surfaces. 198 42

Immunological studies were designed to study the structure of the oligomycin sensitivity conferring protein (OSCP) integrated in the mitochondrial ATPase-ATPsynthase complex. The monoclonal antibody 2B1B1 used in this study could bind as well to purified or membrane bound OSCP as shown previously by Protein A-gold immunocytochemistry and by competitive immunotitration. In this paper, it is shown that 2B1B1 can also immunoprecipitate the F0F1 complex from a Triton X-100 extract. This means that not only, 2B1B1 binds to the surface of OSCP but also that the binding of 2B1B1 did not destroy the interactions between F0 and F1 and further demonstrates the external location of the 2B1B1 binding site in the ATPase-ATPsynthase complex. This antigenic site was located on the N-terminal sequence of OSCP, between residues 1 and 72, as demonstrated after chemical cleavage of OSCP with formic acid, hydroxylamine and partial cleavage with cyanogen bromide. The proximity of Tyr and Arg to the epitope was suggested by the lack of 2B1B1 binding to iodinated OSCP and by the susceptibility of this binding to trypsin or to endoproteinase Arg-C treatments of OSCP, respectively. A more precise location of the epitope has been attempted by using the method of synthesis of overlapping octapeptides on solid support. It was found that 2 groups of octapeptides could bind 2B1B1. The first group contained in common the sequence Pro7-Pro8-Val9-Gln10-Ile11-Tyr12- and the second group of peptides contained the sequence Arg62-Ser63-Val64-Lys65. Another monoclonal antibody, AF4H7, which competes with 2B1B1, also recognized the first group of peptides. The possible involvement of these 2 fragments in the epitope localized at the surface of OSCP is discussed. In addition, secondary structure theoretical analysis predicts that these 2 domains should be in a beta-strand configuration.
...
PMID:Epitope of OSCP oligomycin sensitivity conferring protein exposed at the surface of the mitochondrial ATPase-ATPsynthase complex. 247 97

To clarify contradicting observations on the identity of inactive renin and prorenin, inactive renin was completely purified from native human chorion laeve and the culture medium of human chorion cells. A 720,000-fold purification with 14% recovery was achieved from chorion laeve in 6 steps, including immunoaffinity chromatography on a monoclonal antibody to human renin coupled to Protein A-Sepharose CL-4B. A 3,100-fold purification with 40% recovery was achieved from chorion culture medium in 4 steps, including immunoaffinity chromatography. Inactive renin purified from the two different sources migrated as a single protein band with the same molecular weight of 47,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and consisted of multiple components that could be resolved by isoelectric focusing. Both had the same pI values which shifted downward upon activation by trypsin; however, relative peak heights were different between the two preparations. The purified inactive renin from chorion laeve was completely inactive and did not bind to pepstatin-aminohexyl-Sepharose; however, that from chorion culture medium was partially active and completely bound to the pepstatin gel, indicating that each molecule is partially activated. Trypsin-activated inactive renins from both sources were identical with human renal renin in terms of pH optimum and Km. Specific activities of trypsin-activated inactive renin from chorion laeve and chorion culture medium were 529 Goldblatt units/mg of protein and 449 Goldblatt units/mg of protein, respectively. Amino acid sequence analysis of both of the purified inactive renin preparations demonstrated a leucine residue at the amino terminus. The sequence of 11 additional amino acids was identical in both and agreed with that predicted from the base sequence of the renin gene. These findings indicate that preprorenin is converted to prorenin following removal of a 23-amino acid signal peptide and that the native inactive renin, whose amino acid sequence commences with Leu-Pro-Thr..., is prorenin.
...
PMID:Pure human inactive renin. Evidence that native inactive renin is prorenin. 267 Sep 24

Actin, myosin, and laminin have been localized in retinal vessels of normal rats by fluorescence microscopy. Actin was localized with the fluorescent F-actin binding toxin nitrobenzoxadiazole phallacidin (NBD-Ph). Indirect immunofluorescence was used to localize myosin and laminin. In addition, laminin localization was also performed with the Protein A-horseradish peroxidase (PA-HRP) method. NBD-Ph staining gave strong fluorescence in both retinal capillaries and larger vessels. Anti-myosin fluorescence could also be observed in trypsin digests of the retinal vasculature. Strong fluorescence of PA-HRP reaction product could be detected in the walls of vessels exposed to anti-laminin antibody. Actin distribution in vessels of the RCS rat with inherited retinal degeneration (retinal dystrophic RCS rat) was also studied. After exposure to NBD-Ph, all capillaries showed fluorescence. However, it was more intense in many of the capillaries in the outer retina, which also appeared morphologically abnormal. Electron microscopy of retinal capillaries fixed in 2.5% glutaraldehyde containing 8% tannic acid revealed numerous microfilaments in the pericyte cytoplasm and some in the basal portion of endothelial cells. In pericytes, these microfilaments are in close association with the endothelial side of the cell. Tangential sections through this region indicate that these filaments may be anchored to the membrane at this site.
...
PMID:Actin, myosin, and laminin localization in retinal vessels of the rat. 352 82

Monoclonal antibody 3A4 to islet cell surface antigen has been previously established in our laboratory, using hybridization of spleen lymphocytes from non-obese diabetic (NOD) mice transferred into immunologically incompetent recipient mice. In the present study, monoclonal islet cell surface antibody 5C12 could be newly obtained in the 10:1 ratio of NOD mice spleen cells and mouse myeloma cells (SP2/0) without any modifications. Protein A radioligand assay and indirect immunofluorescence on living cells showed that 5C12 antibody reacted to normal rat islet cells and cultured rat insulinoma cells (RIN-r), but not to cultured lymphocytes (Bri-7, IM-9) and Chang-liver cells. Analysis of 125I-labeled antibody binding revealed that unlabeled 5C12 effectively inhibited subsequent 125I-5C12 binding to RIN-r cells, whereas unlabeled 3A4 did not. The scatchard plot from these data showed the curvilinearity, and about 150,000 binding sites to antibody per RIN-r cell were counted. The treatment of RIN-r cells with papain and neuraminidase reduced the binding of 5C12 to RIN-r cells, whereas the effect of trypsin was not observed. Immunoprecipitation of 125I-labeled insulinoma cell lysates followed by SDS-PAGE and autoradiography indicated that 5C12 recognized 105K dalton cell surface protein in RIN-r cells. Immunoblotting also showed that 5C12 antibody recognized 105K dalton cell surface protein in RIN-r cells. These results demonstrated that 5C12 was an important tool for clarifying the immunoresponse against certain antigenic determinants on pancreatic B cells. Furthermore, 5C12 has not only qualitatively and quantitatively improved diagnostic methodology, but it may also provide new reagents useful to the treatment and prevention of type 1 diabetes.
...
PMID:[An analysis of islet cell surface antigen defined by monoclonal islet cell surface antibody 5C12]. 354 94


1 2 3 Next >>

---