Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

As in the case of retinol, low doses of cholecalcipherol and alpha-tocopherol "in vitro" increase the osmotic resistance of red blood cells, while high doses have a lytic effect on the erythrocytes of various animal species (e.g.: man, sheep, rabbit, guinea-pig, mouse, rat) with the exception of the chicken. The haemolytic effect of cholecalcipherol is less intense than that of retinol; alpha-tochopherol, while causing even less haemolysis than cholecalcipherol, involves a remarkable loss of K+ from the red cells. Besides these quantitative differences, the mechanism of action of the three vitamins seems somewhat different, as shown by modifications of the suspension medium (e.g.: pH, temperature, presence of proteins and reducing substances) or by treatment of the red cells with trypsin. Our results therefore essentially confirm the hypothesis of Dingle and Lucy of common mechanism of action of liposoluble vitamins on biological membranes.
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PMID:[Effect of vitamin D and vitamin E on the erythrocyte membrane. I. Effect on in vitro osmolar resistance and lysis]. 4 Apr 12

The use of derived and synthetic peptides has contributed greatly to our understanding of encephalitogenic determinants in the basic protein molecule. Peptides derived from BP by use of trypsin, pepsin, cathepsin D (brain and liver) and BNPS-skatole have proven most useful. Synthetic peptides have served to define the disease-inducing determinants with precision. A remarkable feature of these studies is that different antigenic determinants serve as encephalitogenic sites in different species. The encephalitogenic sites comprise short peptide domains of the BP polypeptide chain, only 8 residues (rat), 9 residues (guinea pig), and 10 residues (rabbit) in length. In view of the requirement for both haptenic and carrier specificity of an immunogenic molecule, it is impressive that these peptides themselves elicit the autoimmune disease, EAE. While less active than BP on a molar basis, they are nonetheless potent encephalitogens, producing clinical signs in rats and guinea pigs at less than 1 microgram dose. The data indicate that for most animal species (guinea pig, rat, monkey) there appears to be only one major encephalitogenic determinant, an unusual finding in view of the number of antigenic determinants for cell-mediated immunity existing in the BP molecule. Possibly a combination of genetic and anatomical factors may account for this phenomenon. A relationship may exist between multiple sclerosis and EAE as shown by peptide studies; lymphocytes are found in MS patients during exacerbation sensitized to the same region of BP active in the monkey. The major encephalitogenic sites are: Guinea Pig (9) Phe-Ser-Trp-Gly-Ala-Glu-Gly-Gln-Lys(Arg); Rabbit (10) Thr-Thr-His-Tyr-Gly-Ser-Leu-Pro-Gln-Lys; Rat (8) Ser-Gln-Arg-Ser-Gln-Asp-Glu-Asn; Monkey (14) Phe-Lys-Leu-Gly-Gly-Arg-Asp-Ser-Arg-Ser-Gly-Ser-Pro-Hser.
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PMID:Peptides and autoimmune disease. 8 85

Purified rat peritoneal mast cells adhere to schistosomula of Schistosoma mansoni which have been pre-incubated in fresh normal rat serum. This cytoadherence reaction is dependent on complement and in particular on components of the alternative pathway. Since antibodies to rat C3 but not IgG block the attachment of the cells to the complement-treated larvae, it appears that C3-specific receptors on the mast cell surface are responsible for the adherence phenomenon. These receptors can also be demonstrated by the rosetting of mast cells with rat complement-treated zymosan particles or fluoresceinated bacteria. The key properties of the receptors are their specificity for homologous (rat) complement, their sensitivity to digestion with trypsin, and their functional dependence on Mg++ ions. Thus, the rat mast cell receptors share many of the characteristics of the C3 receptors previously identified on monocytes, macrophages, and polymorphonuclear leukocytes.
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PMID:Receptors for C3 on rat peritoneal mast cells. 40 3

Prolactin binding sites have been reported in a variety of tissues that are hormonally responsive to prolactin (PRL). A synergistic effect of PRL and androgens upon the secondary sexual structures of the male rat has been demonstrated. The present study was designed to: 1) determine if there are PRL binding sites in a membrane-rich particulate fraction of the rat ventral prostate: and 2) study the effect of changing the hormonal environment upon this specific PRL binding. The binding of lactoperoxidase iodinated ovine prolactin (I125-PRL) to rat prostatic membrane preparations was assayed by the method of Shiu and Friesen. Serum LH and PRL were measured by radioimmunoassay. The specific binding of I125-PRL that was observed in the prostatic membrane preparation of intact adult male rats was readily displaced by excess unlabelled ovine or rat PRL but not by rat LH or FSH. This binding was decreased by heating or trypsin treatment of the membrane preparation. Tissue specificity was demonstrated in that no specific binding was observed in membrane preparations of lung or spleen from these male rats. Prostatic membrane preparations from adult rats that were castrated for either 4 or 8 days showed a 90% decrease in specific I125-PRL binding while serum PRL values were not changed. Daily subcutaneous administration of testosterone propionate (2.0 mg/rat) to 4-day castrated adult rats resulted in I125-PRL binding comparable to that of intact rats. The data show that a reduction of endogenous androgens results in diminished I125-PRL binding in the ventral prostate of the rat.
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PMID:Prolactin binding in the rat ventral prostate. 81 36

Chicken leg muscle parvalbumin was digested with cyanogen bromide or trypsin or trypsin after citraconylation. Peptides isolated by reverse phase HPLC at pH 7.0 were subjected to acid hydrolysis and amino acid analysis and, in some cases, sequencing. The chicken muscle parvalbumin amino acid sequence has ca. 80% sequence identity with alpha-type parvalbumins from mammalian (rabbit, human and rat) muscle. By contrast, the chicken thymus parvalbumin ("avian thymic hormone") sequence is very similar to reptile (turtle, salamander and frog) muscle beta-type parvalbumins. We hypothesize that the evolutionary appearance of the warm-blooded reptiles was accompanied by recruitment of the beta parvalbumin isozyme for promotion of lymphocyte maturation.
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PMID:Comparison of the amino acid sequences of tissue-specific parvalbumins from chicken muscle and thymus and possible evolutionary significance. 195 91

Parathyroid hypertensive factor (PHF) is a newly described hypertensive factor that may be related to elevation of blood pressure in 30-40% of North American essential hypertensive patients. PHF is also found in several animal models of hypertension, including spontaneously hypertensive rats, and deoxycorticosterone acetate salt hypertensive rats. Plasma collected from spontaneously hypertensive rats (SHR) was used in the present study for purification of PHF. Plasma was dialyzed at a molecular mass cutoff of 1 kDa, and then ultrafiltered at a molecular mass cutoff of 5 kDa. PHF activity, as determined by bioassay (characteristic delayed hypertensive response in normotensive rat) was retained in the fraction that was greater than 1 kDa and less than 5 kDa. Dialyzed and ultrafiltered SHR plasma was fractionated by molecular-exclusion chromatography, either with Bio-Gel P-6 liquid chromatography, or TSK 2000 SW HPLC. The biological activity was detected in a discrete region corresponding to a molecular mass of 2.5-3 kDa. When the molecular-exclusion fraction was subsequently fractionated by reverse-phase HPLC, biological activity was located in a single discrete peak, which did not occur in plasma from normotensive rats prepared in a similar manner. The biologically active fraction of PHF was inactivated by trypsin; this and its UV spectrum indicate the presence of a peptide structure.
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PMID:Purification of parathyroid hypertensive factor from plasma of spontaneously hypertensive rats. 206 15

Two colon cancer cell lines, HT-29 (human) and DHD/K12/TRb (rat), were grown as monolayer cultures to various confluence degrees. The cytotoxic efficacies of doxorubicin and 4'-deoxydoxorubicin, evaluated by a survival assay, and the nuclear drug concentrations, measured by microspectrofluorometry, were shown to progressively decrease with the augmentation of confluence. This confluence dependent resistance (CDR) to anthracyclines was demonstrated independent of the multidrug resistance drug efflux mechanism. The cellular uptake of three compounds (sodium [51Cr]chromate, D-[14C]alanine, L-[14C]glucose) known to passively diffuse across the cell membrane as anthracyclines do was also reduced in confluent cells. After trypsin cell detachment, the kinetics of reversion of the sodium [51Cr]chromate uptake decrease and that of CDR were similar. Therefore, CDR may be attributed to a reduction of anthracycline cell intake due to a general alteration of passive diffusion across the cell membrane. However, CDR is only partly explained by this phenomenon since a reduced sensitivity of confluent cells was observed compared with nonconfluent cells for a similar amount of drug in their nuclei. CDR could explain the high resistance to anthracyclines of some solid tumors, such as colon tumors, in which cancer cells are tightly aggregated.
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PMID:Mechanisms of resistance of confluent human and rat colon cancer cells to anthracyclines: alteration of drug passive diffusion. 220 25

A protease extract from Antarctic krill (E. superba) intended as a new enzymatic debrider for necrotic ulcers has been characterized by sodium dodecyl sulphate polyacrylamide gradient gel electrophoresis and fast protein liquid chromatography. The predominant enzymes in the preparation represent trypsin-like activity associated with three serine proteinases. In addition two carboxypeptidases A and B are present as cooperative enzymes for a more complete breakdown of complex proteinaceous substrates. Biological studies on a well-defined substrate (fibrin) originating from leg ulcers, demonstrated more effective degradation by krill enzymes than bovine trypsin, a common component in marketed enzymatic debriders. These findings support previously in vitro/in vivo studies in an animal model (rat) using excised rat skin as "necrotic" tissue.
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PMID:Biochemical and biological profile of a new enzyme preparation from Antarctic krill (E. superba) suitable for debridement of ulcerative lesions. 277 38

Several investigators have reported the appearance of hypertrophic type II cells in the lungs of silica-treated rats. The purpose of this study was to isolate and characterize these hypertrophic type II cells. Lungs were digested with trypsin and the released cells were separated by using a flow gradient during centrifugal elutriation. Type II cells from control lungs were distributed in the flow gradient as a single population, whereas type II cells from the lungs of silica-treated rats had a bimodal distribution suggesting the presence of two distinct populations of type II cells; one of these populations appeared hypertrophic (type IIB) and the other appeared normal (type II cells; one of these populations appeared hypertrophic (type IIB) and the other appeared normal (type IIA). These two populations of type II cells from silica-treated rats differed significantly in cell size and their lamellar body content. The mean volume of type IIA and type IIB cells was 350 +/- 38 micron 3 and 523 +/- 29 micron 3, respectively. The mean number of lamellar bodies in type IIA and type IIB cells was 77 +/- 53 and 131 +/- 84 per cell, respectively. The mean volume of lamellar bodies was 0.39 +/- 0.09 micron 3 in type IIA cells and 0.66 +/- 0.10 micron 3 in type IIB cells. Type IIA cells were not significantly different from type II cells from the lungs of untreated rats. The distribution of type II cells from silica-treated lungs was such that 2 weeks after a single intratracheal injection of silica (10 mg/rat) type IIB cells accounted for 39.2 +/- 6.4% of the total type II cells recovered after centrifugal elutriation. The general morphological appearance of the isolated type IIA and type IIB cells was similar to that observed in type II cells isolated from untreated rats. These data indicate that hypertrophic type II cells may be isolated from the lungs of silica-treated rats and separated from normal type II cells thus allowing the role of these unusual type II cells in lung injury and repair to be investigated.
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PMID:Silica-induced hypertrophy of type II cells in the lungs of rats. 301 7

Cytochalasin B and nitrobenzylthioinosine (NBMPR), which inhibit membrane transport of glucose and nucleosides, respectively, have served as photoaffinity ligands that become covalently linked at inhibitor binding sites on transporter-associated proteins. Thus, when membranes from erythrocytes of neonatal pigs with site-bound [3H]cytochalasin B or [3H]NBMPR were irradiated with uv light, two labeled membrane polypeptides (peak Mr values: 55,000 and 64,000, respectively) were identified. Treatment of the photolabeled membranes with endoglycosidase F increased the mobility of [3H]cytochalasin B- and [3H]NBMPR-labeled material (peak Mr values: 44,000 and 57,000, respectively) and limited digestion with trypsin yielded different polypeptide fragments (Mr values: 18,000-23,000 and 43,000, respectively). Identification of the photolabeled polypeptides as transporter components was established using monoclonal antibodies (MAbs) raised against partially purified preparations of band 4.5 from erythrocytes of adult pigs and humans. MAbs 65D4 and 64C7 (anti-human band 4.5), raised in this study, reacted with [3H]cytochalasin B-labeled material from membranes of human erythrocytes and bound to permeabilized erythrocytes but not to intact cells. MAb 65D4 also bound to erythrocytes of mice and neonatal pigs and to a variety of cultured cells (mouse, human, rat), including AE1 mouse lymphoma cells, which lack an NBMPR-sensitive nucleoside transporter. Also employed was MAb 11C4 (anti-pig band 4.5), which recognizes the NBMPR-binding protein of erythrocyte membranes from adult pigs. When membrane proteins from neonatal and adult pigs were subjected to electrophoretic analysis and blots were probed with different MAbs, MAb 65D4 (anti-human band 4.5) bound to material that comigrated with [3H]cytochalasin B-labeled polypeptides (band 4.5) from neonatal, but not adult, pig erythrocytes, whereas MAb 11C4 (anti-pig band 4.5) bound to material that comigrated with [3H]NBMPR-labeled band 4.5 polypeptides of erythrocytes from both neonatal and adult pigs. These results, which indicate structural differences in the cytochalasin B- and NBMPR-binding proteins of pig erythrocytes, establish the presence of both proteins in erythrocytes of neonatal pigs and suggest that only the NBMPR-binding protein is present in erythrocytes of adult pigs.
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PMID:Identification of glucose and nucleoside transport proteins in neonatal pig erythrocytes using monoclonal antibodies against band 4.5 polypeptides of adult human and pig erythrocytes. 314 74


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