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)

Insulin, a mitogen for cultured chick embryo fibroblasts (Temin, H.M. (1968) Cancer 3, 771-787), has been employed to characterize the effects of mitogen/cell membrane interactions as it relates to growth. The specific binding of 125I-insulin to substratum-attached cells is time- and temperature dependent and is optimum at a pH of 7.0. Fetal calf and chicken sera, somatomedin "A/C mixed," and desalanine or native porcine insulin compete with 125I-insulin for membrane-binding sites. Proinsulin, although competing less effectively than native insulin for binding, is more effective than desoctapeptide insulin. Unrelated polypeptide hormones do not compete for 125I-insulin binding. The lowest concentration of insulin at which specific binding is detected is 0.1 nM. Scatchard plot analysis of the binding data indicates that there are two types of binding sites in confluent cultures of fibroblasts: one of high affinity (K1 = 2 to 6 X 10(8) M-1) and low capacity, the other of low affinity (K2 = 0.8 to 3.0 X 10(7) M-1) and high capacity. Approximately 1.9 and 7.1 X 10(3) molecules of insulin are bound at each site, respectively. A 10-min incubation at 24 degrees of the fibroblasts with 10 mug/ml of trypsin causes a 2-fold stimulation of specific 125I-insulin binding and a similar 2-fold increase in insulin-stimulated 2-deoxy-D-glucose uptake and thymidine incorporation. Neuraminidase treatment also produces a 37% increase in specific 125I-insulin binding but treatment with alpha-chymotrypsin or phospholipase C are without significant effect. The results of this and additional experiments support the hypothesis that trypsin treatment of chick embryo fibroblasts leads to an unmasking of 125I-insulin binding sites. Serum starvation of fibroblasts for 12 or 24 h produces a 2.5- to 5-fold increase in specific 125I-insulin binding. This increase is the result of an increase in the number of hormone-binding sites from 9 X 10(3) to 6 X 10(4) per cell which are predominantly of the low affinity type. There is no change in the affinity constants. The presence of camptothecin, or cordycepin, or cycloheximide in the incubation medium completely blocks the increase in number of 125I-insulin-binding sites resulting from serum starvation. The addition of native insulin to the medium of serum-starved cultures also blocks this increase. The magnitude of insulin-stimulated 2-deoxy-D-glucose uptake and thymidine incorporation correlates with the levels of occupancy of the low affinity 125I-insulin-binding sites in untreated fibroblasts. In fibroblasts cultured in the absence of serum, the marked increase in insulin-stimulated 2-deoxy-D-glucose uptake and thymidine incorporation parallels the increase in number of mitogen receptors. The concentration of insulin that produces a half-maximum stimulation of thymidine incorporation is calculated to be 5 X 10(-8) M. At this concentration of insulin, 42% of the receptor sites are occupied.
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PMID:Mitogen receptors in chick embryo fibroblasts. Kinetics, specificity, unmasking, and synthesis of 125I-insulin binding sites. 98 22

Tumor cells and urine-voided cells from patients with invasive bladder carcinoma as well as from healthy patients were examined cytologically, ultrastructurally and immunocytochemically. The ultrastructure of tumor cells showed an abundant, dilated, rough endoplasmic reticulum in the form of membrane-bound vacuoles full of granular to fibrillar material located perinuclearly and/or paranuclearly. Some cells exhibited enlarged modified lysosomes containing sparce flocculent and particulate precipitate. Papanicolaou staining of these cells showed two basophilic cytoplasmic textures, one green glossy-patchy, perinuclearly and/or paranuclearly, well segregated from the other texture of peripheral hematoxylinophilic foamy cytoplasm, comparable to the cytologic features of cell cultures originating in invasive bladder carcinoma. PAS diastase showed double distribution and texture of the perinuclear glycosaminoglycans, a glossy accumulated mass and large granules. Glycosaminoglycan sacs similar to those of cell cultures were also present in tumor-dispersed cells. There was a nonspecific binding of antisera against lysozyme, human chorionic gonadotropin and alpha 1-trypsin in normal and tumor cells. Tumor cells and tissues were positive for alpha 1-chymotrypsin distributed perinuclearly and in large spheres. Normal cells lacked the above characteristics. The results indicate that it is feasible to use the aforementioned characteristics in conjunction with the existing bladder-cytologic criteria for malignancy as markers in urothelial cancer with regard to prognosis of superficial tumors with high malignant potential.
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PMID:A cytologic, ultrastructural and immunocytochemical comparison of tumor cells and cell cultures originating in invasive bladder carcinoma. 137 23

The possible mitogenic activity of fibronectin (FN) in human primary and metastatic melanoma lines and clones and the involvement of integrins in mediating this effect were evaluated. Quescent human melanoma cells cultured in serum-free medium proliferated in a dose- and time-dependent fashion to immobilized FN as indicated by [3H]thymidine incorporation, increment of cell number, and cell cycle analysis. This response to FN was observed with tumor clones isolated from a subcutaneous metastasis and with primary or metastatic melanomas from different patients, but only when tumor cells expressed the alpha 5 subunit of the FN receptor (i.e., VLA-5). Proliferation to FN by a primary tumor (Me4405) expressing all FN receptors and by a tumor clone (2/60) lacking only the alpha 4 subunit was inhibited by monoclonal antibodies to the alpha 5 and beta 1 but not by monoclonal antibodies to other subunits of FN receptors. Mapping of FN regions responsible for the proliferative signal was performed by stimulating melanoma cells with different FN proteolytic fragments and indicated that a significant mitogenic signal was provided by the M(r) 120,000 alpha-chymotrypsin fragment containing the Arg-Gly-Asp sequence. The proliferation of melanoma cells to FN and to FN fragments was also significantly inhibited by peptides containing the Arg-Gly-Asp sequence. These data indicate that FN can stimulate the proliferation of quiescent melanoma cells and that integrins as alpha 5 beta 1 are involved in the response of tumor cells to this extracellular matrix protein.
Cancer Res 1992 Aug 15
PMID:Role of the alpha 5 beta 1 integrin receptor in the proliferative response of quiescent human melanoma cells to fibronectin. 138 57

We have investigated the ability of Bowman-Birk inhibitor, a protease (trypsin and chymotrypsin) inhibitor, to protect against radiation-induced thymic lymphosarcoma in C57Bl/6NCr1BR mice. Fifty-five 7-week-old male mice were randomized into 11 groups and gavaged 5 days per week with purified Bowman-Birk inhibitor, Bowman-Birk inhibitor concentrate, and autoclaved Bowman-Birk inhibitor concentrate. Following 7 days of gavage, those mice undergoing total-body or sham total-body irradiation received 1.7 Gy weekly for 4 weeks. At 6 months following the radiation exposure, all mice were sacrificed and examined histopathologically. Samples of Bowman-Birk inhibitor concentrate, purified Bowman-Birk inhibitor, and autoclaved Bowman-Birk inhibitor concentrate were evaluated with thin-layer chromatography. The mice treated with total-body irradiation and autoclaved Bowman-Birk inhibitor had significantly (P < 0.05) fewer deaths, lower average grade of lymphosarcoma, and larger fat stores compared to those treated with total-body irradiation and water gavage. The results for the total-body-irradiated mice receiving Bowman-Birk inhibitor concentrate suggested an effect midway between these two groups. Thin-layer chromatography analysis indicated that sterols and the phospholipids varied in the three different samples in a way that approximately corresponded with the observed effects. We have observed that an autoclave-resistant factor in soybeans is capable of reducing metastasis of radiation-induced lymphosarcoma and weight loss in C57Bl/6NCr1BR mice, presumably by preventing the extension and metastasis of cancer cells. Thus, in addition to the anticarcinogenic Bowman-Birk inhibitor, there appears to be another anticarcinogenic agent in soybeans which is capable of inhibiting the later stages of cancer cell development.
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PMID:Protection against metastasis of radiation-induced thymic lymphosarcoma and weight loss in C57Bl/6NCr1BR mice by an autoclave-resistant factor present in soybeans. 143 9

The replacement of genetically deficient enzymes in patients with inherited metabolic disorders by infusion of purified enzymes or by organ transplantation has had very limited success, although good results with bone marrow transplantation have been obtained in some patients with mucopolysaccharidosis, Gaucher disease and inherited immunodeficiency diseases. Genetic engineering of the patient's lymphocytes may ultimately render these approaches redundant, at least for some of these diseases. Treatment of chronic pancreatic insufficiency and of disaccharidase deficiency with oral enzymes can be very effective; therapy can be monitored in the latter by measuring the breath hydrogen excretion and in the former by a range of tests of which stool chymotrypsin assay is the most convenient. Treatment of acute myocardial infarction by intracoronary perfusion of thrombolytic enzymes can improve both cardiac function and long-term survival if given early enough. Successful reperfusion can be identified by changes in the kinetics of serum enzyme release and clearance, especially for the isoenzymes and isoforms of creatine kinase. In cancer chemotherapy, L-asparaginase has long been a useful adjunct in the treatment of acute lymphoblastic leukemia, but recent experience suggests a role in acute nonlymphoblastic leukemia as well.
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PMID:Enzymes as agents for the treatment of disease. 157 79

In this study, the distribution of the soybean-derived Bowman Birk inhibitor (BBI) in mice was examined. Mice received [125I]BBI by oral gavage and three hours later, the mice were sacrificed, the organs of interest were carefully removed and the distribution of the inhibitor was determined. The bulk of labeled BBI was present in the luminal contents of the small and large bowel, urine and feces. Significant amounts of label were also observed in the serum, esophagus, stomach and intestine, kidney, liver and lung. Analysis of tissue homogenates by gel filtration chromatography revealed that the radioactivity eluted from the column at the same position as the BBI standard indicating that the iodinated BBI was still intact. The chromatographically purified BBI was able to inhibit chymotrypsin indicating that functional protease inhibitory activity was present. These results indicate that the BBI becomes widely distributed in mice 3 h after oral administration and that intact protease inhibitor is present in internal organs.
Cancer Lett 1992 Mar 15
PMID:Distribution of the Bowman Birk protease inhibitor in mice following oral administration. 159 63

The ornithine decarboxylase-inducing factor (ODC factor) was purified about 1,000-fold in 42% yield from the ascites fluids of an Ehrlich ascites tumor by a combination of centrifugation and concanavalin A (ConA) treatment. A single ip injection of 0.5 micrograms of the purified factor per mouse resulted in half-maximum induction of liver ODC. The factor was found to be a trypsin- and chymotrypsin-resistant, acidic glycoprotein (pI about 4.43) with a minimum molecular weight of about 70 kilodaltons, containing a disulfide bond(s) in its functional domain. It did not react with ConA. This factor induced retrodifferentiation of liver function, causing a marked increase of prototype M2 isozyme of pyruvate kinase. It reduced liver catalase activity, and also modified thyroid hormone metabolism, reducing the serum levels of T4 and T3. These results suggest that the ODC factor is multifunctional and induces many of the changes observed in a tumor-bearing host.
Jpn J Cancer Res 1991 Mar
PMID:Purification of ornithine decarboxylase-inducing factor from cell-free ascites fluid of Ehrlich ascites tumor and its characteristics. 170 56

We have shown that depletion of monocytes from human peripheral blood mononuclear cells (PBMC) by L-phenylalanine methyl ester (PheOMe) enhanced lymphokine-activated killer cell (LAK) generation by recombinant interleukin-2 (rIL-2) at high cell density. In this study, we have investigated the mechanism of action of PheOMe on LAK activation by using trypsin, chymotrypsin, tosylphenylalaninechloromethanol (TPCK, a chymotrypsin inhibitor), tosyl-L-lysinechloromethane (TLCK, a trypsin inhibitor), phenylalaninol (PheOH), and benzamidine. PBMC were treated with 1-5 mM PheOMe for 40 min at room temperature in combination with the various agents, washed and assessed for their effects on natural killer (NK) activity against K562 cells and monocyte depletion. The treated cells were then cultured with or without rIL-2 for 3 days. LAK cytotoxicity was assayed against 51Cr-labeled K562 and Raji tumor target cells. TPCK at 10 micrograms/ml partially inhibited depletion of monocytes by PheOMe. TLCK did not prevent depletion of monocytes nor inhibition of NK activity induced by PheOMe. TPCK and TLCK inhibited NK activity by themselves. TPCK but not TLCK inhibited rIL-2 induction of LAK cells. On the other hand, PheOH and benzamidine (analogs of PheOMe) lacked any effect on monocyte depletion but abrogated the inhibitory effect of PheOMe on NK activity. They had no effect on rIL-2 activation of LAK activity enhanced by PheOMe. Trypsin potentiated the inhibitory effect of PheOMe on NK activity and monocyte depletion. Trypsin partially inhibited IL-2 activation of LAK activity enhanced by PheOMe. Chymotrypsin had little effect on NK activity but prevented the inhibitory effect of PheOMe on NK activity. It had little effect on monocyte depletion induced by PheOMe. PheOMe was hydrolysed by monocytes and chymotrypsin to Phe and methanol as determined by HPLC. TPCK inhibited hydrolysis of PheOMe by monocytes. Our data suggest that the effects of PheOMe on monocytes, NK cells and LAK activation involve protease activities of monocytes.
Cancer Immunol Immunother 1991
PMID:Human lymphokine-activated killer (LAK) cells: III. Effect of L-phenylalanine methyl ester on LAK cell activation from human peripheral blood mononuclear cells: possible protease involvement of monocytes, natural killer cells and LAK cells. 176 Aug 8

Protease inhibitors have been shown to be effective suppressors of carcinogenesis in vitro and in vivo. For example, the soybean-derived Bowman-Birk inhibitor (BBI) suppresses dimethylhydrazine-induced colon carcinogenesis in mice. Relatively little is known about the effects of protease inhibitors on intestinal epithelial cells. In the present study, we have investigated the interaction of the anticarcinogenic BBI with intestinal epithelial cells. At the concentrations examined, BBI was non-toxic and had no effect on the doubling time, saturation density or rate of DNA synthesis by these cells. This compound was taken up by these cells in a time dependent manner and was present in the cells for 12 h following a 2 h incubation with BBI. Subcellular fractionation experiments demonstrated that the bulk of the internalised inhibitor was present in the cytosol. Analysis of BBI from treated cells on a chymotrypsin affinity column revealed that active inhibitor was present in the cells. Our results indicate that the BBI is internalised by colonic epithelial cells which would allow BBI to inhibit critical intracellular proteases and thus suppress malignant transformation.
Eur J Cancer 1991
PMID:Internalisation of the Bowman-Birk protease inhibitor by intestinal epithelial cells. 183 26

A protein factor which stimulated [3H]thymidine uptake into free hepatocytes prepared from normal mouse liver was detected in the ascitic fluid of gynecological cancer patients. The factor was subsequently further purified from the ascitic fluid of an endometrial cancer patient by DEAE-Sephacel, Sephadex G-150 and Phenyl-Sepharose CL-4B column chromatographies, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed a single protein band of 54,000 Da, designated tentatively as 54K ascitic protein (54K-AP). 54K-AP was similar to human alpha 1-antitrypsin (alpha 1-AT) in terms of SDS-PAGE and immunological behavior, but was slightly different in terms of amino acid sequence and isoelectric point. Although 54K-AP inhibited the activities of bovine trypsin and alpha-chymotrypsin as did human alpha 1-AT, 54K-AP inhibited the plasminogen activator released from human endometrial cancer Ishikawa cells more efficiently than alpha 1-AT. Because, in contrast to normal serum, the serum from the endometrial cancer patients stimulated [3H]thymidine uptake into hepatocytes, the possibility arises that 54K-AP could be produced by the cancer host as a defence mechanism against the cancer.
Jpn J Cancer Res 1991 Jun
PMID:Characterization of a 54 kDa, alpha 1-antitrypsin-like protein isolated from ascitic fluid of an endometrial cancer patient. 190 55


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