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:3.4.21.1 (chymotrypsin)
10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In two cases of solid and papillary neoplasm of the pancreas (SPN), positive staining for argyrophil granules, chromogranin-A, neuron-specific enolase, chymotrypsin, alpha 1-antitrypsin, vimentin, cytokeratin, and estrogen receptors was present. Ultrastructurally, neurosecretory as well as zymogenlike granules were demonstrated. Measurements of mean nuclear volume and volume-corrected mitotic index discriminated between SPN and well-differentiated ductal adenocarcinoma of the pancreas, with notably lower values being seen in SPN. Silver-stained nucleolar organizer region counts showed wide overlaps. The results suggest that SPN is a tumor with mixed endocrine and exocrine features. Its low malignant potential compared to ductal adenocarcinoma is reflected in the mean nuclear volume and volume-corrected mitotic index. The presence of estrogen receptors may prove therapeutically useful.
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PMID:Solid and papillary neoplasm of the pancreas. 144 85

Previous studies have shown that the non-alpha-helical, amino-terminal head region of vimentin is essential for the formation and stability of vimentin intermediate filaments (IFs). In order to specify its target site on companion protein subunits, it was cut off from vimentin at amino acid position 96 with lysine-specific endoproteinase and allowed to react with intact vimentin and other IF proteins. In solution of high salt concentration (500 mM KCl), the isolated polypeptide (vim NT) showed a high affinity for all cytoplasmic IF proteins tested, but not for nuclear lamins. Employing limited digestion of the IF proteins with different proteinases, the binding site was shown to reside in their alpha-helical rod domains. Other polypeptides possessing alpha-helical regions with the potential to form coiled-coil structures like tropomyosin and myosin subfragment 2 did not react with vim NT. The binding to IF proteins was strongly inhibited by phosphorylation of vim NT and totally abolished in the presence of 200 mM arginine hydrochloride, whereas the same concentration of lysine hydrochloride was ineffective. Limited chymotryptic digestion of vim NT produced polypeptides that were unable to react with the alpha-helical region of vimentin at high salt concentration. Consistent with these observations, vim NT strongly inhibited filament formation in vitro from protofilamentous vimentin. A 14-mer oligopeptide comprising the amino acids 3 to 16 of the amino terminus also inhibited filament formation, though to a lesser extent. Conversely, vim NT and, with a lower efficiency, the 14-mer oligopeptide also severely affected the structure of preformed vimentin filaments by unraveling them. Phosphorylated vim NT was considerably less active in this respect. Further digestion of the rod domain of vimentin with chymotrypsin yielded 17.4 and 21 kDa polypeptides, which were tentatively characterized as originating from the carboxy- and amino-terminal half of the rod domain, respectively. Both formed salt-stable complexes with vim NT, the smaller polypeptide with a higher efficiency than the larger one. These results suggest that the staggered, antiparallel arrangement of the two coiled-coils in the protofilaments of IF proteins is, at least in part, determined by the twofold, symmetrical association of the amino-terminal head regions of one coiled-coil rope structure with the carboxy-terminal halves of the alpha-helical rod domains of the other coiled-coil and that similar interactions occur during filament assembly and in the intact filament.
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PMID:Salt-stable interaction of the amino-terminal head region of vimentin with the alpha-helical rod domain of cytoplasmic intermediate filament proteins and its relevance to protofilament structure and filament formation and stability. 162 50

Immunocytochemistry was used to examine 18 cases of rat fibrous histiocytic tumours (11 malignant; seven benign). The diagnosis was made by light microscopic criteria and all cases were categorized as pleomorphic-storiform. A selection of polyclonal antibodies to histiocytic, muscle, neural and mesenchymal antigens was used. Fifteen tumours were positive with alpha 1-antitrypsin, four with alpha 1-chymotrypsin, ten with muramidase, five with desmin, 15 with neuron-specific enolase, 14 with S100, one with glial fibrillary acid protein and 12 with vimentin. Many tumours expressed several antigens, highlighting the confusion which has arisen with regard to the histiogenesis of fibrous histiocytic tumours in man, and supporting the concept of differentiation from a primitive mesenchymal common precursor able to differentiate in several directions.
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PMID:An immunohistochemical study of spontaneous histiocytic tumours in the rat. 165 Aug 3

Clear cell chondrosarcoma, a subtype and separate entity from the conventional chondrosarcoma, is characterized by its special histologic features, site of predilection, slow growth and better prognosis. Three cases are presented with elucidation of clinicopathologic correlation and detection by ABC immunohistochemical method using several antibodies. The observation of positive reaction to S-100 protein, vimentin, anti-alpha-chymotrypsin and Lysozyme by the tumor cells of clear cell chondrosarcoma, similar to chondrosarcoma and chondroblastoma, proves that this tumor has its origin from the cartilaginous tissue. It was found for the first time that the clear cell chondrosarcoma was positive for wheat germ agglutinin and concanavalin A. The authors believe that clear cell chondrosarcoma may result from the anaplastic change of chondroblastoma cells into another subtype of that tumor. The osteoblastlike multinucleated giant cells, retaining the antigens of phagocytes, are not considered to be neoplastic.
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PMID:[Immunohistochemical study on clear cell chondrosarcoma]. 180 53

Three cases of "dedifferentiated" chordoma arising in the sacrococcygeal region are presented. In all three cases, the "dedifferentiated" component arose de novo in conjunction with conventional chordoma. Two of these patients, whose tumors had a prominent malignant fibrous histiocytoma (MFH) component, died within 6 months of diagnosis. Both patients had lung metastases, one of which was histologically documented to be MFH. The third patient, whose initial tumor contained osteosarcoma, died 76 months after diagnosis and multiple recurrences. Most notable in this case was the absence of the "dedifferentiated" component (in this instance, osteosarcoma) in all of the local recurrences as well as the lung metastases. These were composed exclusively of conventional chordoma. None of the patients had a previous history of radiation therapy. The immunohistochemical staining pattern of conventional chordoma was similar to that of previous reports, where the epithelial-like cells stained for cytokeratin and epithelial membrane antigen. In addition, they stained for alpha-1-anti-chymotrypsin and vimentin. These latter two markers were also identified in the "dedifferentiated" component. As with "dedifferentiated" chondrosarcomas and liposarcomas, "dedifferentiation" in a chordoma usually portends an accelerated clinical course.
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PMID:"Dedifferentiated" chordoma. A clinicopathologic and immunohistochemical study of three cases. 244 Mar 24

The immunoperoxidase avidin-biotin-peroxidase complex method was used to investigate the presence of histiocyte markers such as lysozyme, alpha-1-antitrypsin (A1AT) and alpha-1-anti-chymotrypsin (A1ACT) and of vimentin, a specific marker for mesenchymal differentiation, in a spontaneous and transplantable rat tumor of supposed fibroblastic-histiocytic origin. Positive staining was obtained for lysozyme and vimentin but A1AT and A1ACT were not demonstrable in any of the tumor sections. These results provide evidence for the fibro-histiocytic nature of the tumor studied and suggest its classification as a malignant fibrous histiocytoma (MFH).
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PMID:Immunohistochemical identification of lysozyme and vimentin in an experimental malignant fibrous histiocytoma. 285 48

The predominant intermediate filament proteins of the goldfish optic nerve have molecular weights of 58K. They can be separated into a series of four major isoelectric variants of neuronal (ON1 and ON2) and nonneuronal (ON3 and ON4) origin. The extent of homology between the goldfish 58K intermediate filament proteins themselves and to rat optic nerve vimentin and glial fibrillary acidic protein (GFAP) was investigated. Unlabeled and [32P]orthophosphate-labeled proteins were subjected to partial hydrolysis by V8 protease, chymotrypsin, and CNBr. The results show that the goldfish intermediate filament proteins share with vimentin and GFAP a 40K chymotrypsin-resistant core fragment. Phosphorylated moieties appear to be located outside the core region since they are preferentially cleaved off by chymotrypsin and not found associated with the 40K core. In addition, the goldfish ON proteins contain the antigenic site within the core that is common to most intermediate filaments. V8 or CNBr digestion indicates that many fragments that are common to ON1 and ON2 are clearly distinct from fragments that are common to ON3 and ON4. In addition, structural variability is observed between the goldfish intermediate filament proteins and vimentin and GFAP. The results are discussed in terms of intermediate filament structure and their possible role in nerve growth.
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PMID:Homology and diversity between intermediate filament proteins of neuronal and nonneuronal origin in goldfish optic nerve. 351 Feb 72

Three cases of clinically benign pancreatic papillary cystic tumors in young female patients were studied by immunohistochemistry and electron microscopy in order to define the cellular nature of this type of neoplasm. Two of the tumors showed focal cytokeratin- and desmoplakin-positivity as evidence of focal epithelial differentiation, while the tumor cells were in all cases positive for vimentin--the intermediate filament protein typical of (but not specific for) mesenchymal cells. Electron microscopy showed some cell-cell junctions, but there was no evidence of acinar or islet cell differentiation. The tumors were at least focally positive for neuron-specific enolase, and small clusters of polypeptide hormone immunoreactive cells were present in all cases (glucagon 3/3, somatostatin 2/3, insulin 2/3). However, the tumors were negative for synaptophysin and neurofilament proteins, unlike most islet cell tumors. Trypsin and chymotrypsin immunoreactivity was found in all tumors, but because many nonpancreatic carcinomas were also positive, we doubt whether these two enzyme proteins can act as specific markers for pancreatic acinar cell differentiation. Two of the tumors that were studied immunohistochemically for the presence of nuclear estrogen receptors, were negative. Therefore no proof of the suggested hormone dependence of this tumor could be obtained. We conclude that papillary cystic tumor is a neoplasm of primitive pancreatic epithelial cells, that may exhibit focal endocrine cell differentiation.
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PMID:Papillary cystic tumor of the pancreas. An analysis of cellular differentiation by electron microscopy and immunohistochemistry. 367 83

Monoclonal antibodies were produced against surface antigens of live cells from a human acute monocytic leukaemia cell line (THP-1). One clone, VIC-C2, when assayed by immunofluorescence microscopy, brightly stained the surface of THP-1 cells and the cytoplasm of Langerhans cells, fibroblasts and melanocytes in sections of human skin. The immunoreactive cytoplasmic structures were filamentous and resembled intermediate filaments. By double immunofluorescence microscopy using VIC-C2 and polyclonal antibodies to vimentin, the VIC-C2 antigen was shown to be located on intermediate filaments of cultured fibroblasts and to follow these filaments during various drug-induced rearrangements. As demonstrated by immunoprecipitation, antibody gel overlay and immunoblotting of two-dimensional polyacrylamide gels, VIC-C2 recognized two different antigens in extracts of THP-1 cells: one of Mr = 43 000 and pI = 7, the other of Mr = 57 000. In extracts from various cultured fibroblast cells only the 57 000 Mr antigen was detected. This 57 000 Mr protein was identified as vimentin by immunoblotting of rat glioma C6 cytoskeletons on two-dimensional gels. When vimentin was digested with chymotrypsin, only fragments containing parts of both helical rod pieces and the connecting non-helical spacer-region were strongly antigenic, whereas the helical rods alone were only weakly crossreactive. Moreover, immunoprecipitation revealed that VIC-C2 preferentially reacted with native compared to denatured vimentin.
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PMID:Monoclonal antibody to a 43 000 Mr surface protein of a human leukaemia cell line (THP-1) crossreacts with the fibroblast intermediate filament protein vimentin. 386 May 6

Intermediate-sized filaments (IF) are among the most insoluble intracellular protein polymer structures. We have analyzed the small amounts of soluble vimentin, an IF protein, present in cytosol fractions obtained from lysis of cultured cells [rat RVF-SM cells, simian virus 40-transformed human fibroblasts, and human rhabdomyosarcoma (RD line) cells]. The molecular form of this soluble vimentin was determined by sucrose density gradient centrifugation, using vimentin-specific antibodies for subsequent ELISA and immunoblotting analyses. The majority of the soluble vimentin appeared in a distinct form indistinguishable in its sedimentation behavior from reconstituted tetrameric subunits of purified vimentin arrested at low ionic strength. The tetrameric coiled-coil nature of the soluble form of vimentin was indicated by the digestion pattern with chymotrypsin and by chemical crosslinking with copper-1,10-phenanthroline and dimethylsuberimidate. The competence of this soluble vimentin to assemble into IF at higher salt concentrations was demonstrated by electron microscopy. Pulse-chase experiments showed that the soluble form was not an exclusively posttranslational intermediate. We propose that in the living cell a small pool of a distinct soluble tetrameric form of vimentin exists which may exchange with polymeric IF vimentin.
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PMID:Identification of a distinct soluble subunit of an intermediate filament protein: tetrameric vimentin from living cells. 386 6


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