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

Matrix metalloproteinases are an important group of zinc enzymes responsible for degradation of the extracellular matrix components such as collagen and proteoglycans in normal embryogenesis and remodeling and in many disease processes such as arthritis, cancer, periodontitis, and osteoporosis. A matrixin family is defined, comprising at least seven members that range in size from Mr 28,000 to 92,000 and are related in gene sequence to collagenase. All family members are secreted as zymogens that lose peptides of about 10,000 daltons upon activation. Latency is due to a conserved cysteine that binds to zinc at the active center. Latency is overcome by physical (chaotropic agents), chemical (HOCl, mercurials), and enzymatic (trypsin, plasmin) treatments that separate the cysteine residue from the zinc. Expression of the metalloproteinases is switched on by a variety of agents acting through regulatory elements of the gene, particularly the AP-1 binding site. A family of protein inhibitors of Mr 28,500 or less binds strongly and stoichiometrically in noncovalent fashion to inhibit members of the family. The serum protein alpha 2-macroglobulin and relatives are also strongly inhibitory.
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PMID:Matrix metalloproteinases and their inhibitors in connective tissue remodeling. 185 Jul 5

Alpha 1-antitrypsin is a serum protein commonly used as a marker of enteric protein loss. In this study, we have quantified alpha 1-antitrypsin concentration in human milk and its excretion by healthy term breast-fed infants. We found high concentrations of alpha 1-antitrypsin in early milk (0.3-0.6 mg/ml during the first week of lactation) while the concentration fell during subsequent weeks, being detectable through at least 3-4 months of lactation. Significant quantities of intact alpha 1-antitrypsin were found to be excreted by the breast-fed infants studied. The amount excreted was typically higher in early weeks (as much as 200 mg/24 h) and decreased with infant age, possibly due to both decreased intake from the milk as well as increased digestion of the protein by the maturing infant. In vitro studies demonstrated that the trypsin-alpha 1-antitrypsin complex resisted proteolysis by pepsin and pancreatic enzymes; thus, alpha 1-antitrypsin in milk can escape gastrointestinal degradation. We conclude that alpha 1-antitrypsin is not a suitable marker for intestinal protein loss by term breast-fed infants.
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PMID:Fecal alpha 1-antitrypsin in breast-fed infants is derived from human milk and is not indicative of enteric protein loss. 232 74

Inter-alpha-trypsin inhibitor (ITI) is a 180 kd serine proteinase inhibitor found in human serum. Treatment of 180 kd ITI with trypsin releases a 30 kd fragment (HI-30) which contains the anti-proteolytic activity of the high molecular weight form. We have isolated a cDNA clone from a human liver library which codes for HI-30, and have determined its DNA sequence. The mRNA not only codes for HI-30 but also another serum protein, alpha-1-microglobulin, which has not been previously associated with ITI or HI-30. The alpha-1-microglobulin sequence is found in the amino-terminus of the protein and is preceded by a signal sequence. HI-30 is found at the carboxy-terminus. The two protein sequences are separated by two arginine residues.
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PMID:The mRNA for a proteinase inhibitor related to the HI-30 domain of inter-alpha-trypsin inhibitor also encodes alpha-1-microglobulin (protein HC). 243 Feb 61

Blood sera of humans, rats, goats, and buffalo have been shown to possess a forward motility-stimulating factor (FMSF) that markedly stimulated goat cauda epididymal sperm forward motility, as assayed by a microscopic method in the presence of epididymal plasma (1.2 mg protein/ml) that had sufficient anti-sticking activity to eliminate the possibility of cell-sticking artifacts in motility assays. The specific activity of FMSF was greatest in buffalo blood serum compared to the sera of the other species. Buffalo serum at a concentration as low as 8.5 mg protein/ml induced forward motility in nearly 45% of the cells. The buffalo serum FMSF was heat-stable, nondialyzable, and sensitive to the action of trypsin. Purified proteins--casein, serum albumin, ovalbumin, myoglobin, and beta-lactoglobulin--showed little or relatively low FMSF activity. FMSF is a glycoprotein, as it binds with high affinity to concanavalin A-agarose. A major portion of the serum protein (approx. 70%) did not bind to the affinity matrix, and this unretained serum protein fraction showed little FMSF activity. The FMSF activity of buffalo serum was confirmed by estimating sperm forward motility spectrophotometrically: an objective method of assessing sperm motility.
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PMID:Stimulation of forward motility of goat cauda epididymal spermatozoa by a serum glycoprotein factor. 262 73

C-reactive protein (CRP) is an acute phase serum protein in man which binds to phosphocholine (PC) in a calcium-dependent manner. CRP has been shown to bind to chromatin and nucleosome core particles. However, CRP does not bind to DNA and there is conflicting evidence regarding the binding of CRP to histones. In the present study, binding of CRP to chromatin was confirmed by ELISA using chromatin bound to microtiter wells. When chromatin depleted of histone H1 was used in the same assay, no CRP binding was detected. Similar results were observed using a competitive inhibition ELISA. These results indicate an important role for H1 in the binding of CRP to chromatin. Further studies were done to characterize the binding of CRP to purified individual histones. CRP binding to histones was demonstrated first by blotting. Calf thymus histones were separated on a 15% SDS-polyacrylamide gel, transferred to nitrocellulose, and probed with 125I-CRP. CRP bound to H1 and H2A and to a lesser extent to H2B. Non-specific binding to H3 was seen and no binding to H4 was observed. CRP binding to purified individual histones was tested by ELISA. Essentially identical results were seen to those obtained by blotting. CRP binding to the H2A-H2B complex was observed as well as reactivity with trypsin-resistant fragments of H2A, H2B, and H3. By blotting and by ELISA all CRP reactions were blocked by PC and EDTA indicating binding through the calcium-dependent PC-binding site on CRP. These studies further characterize the nature of the binding of CRP to chromatin and histones and show that the presence of H1 on chromatin is required for CRP binding.
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PMID:Analysis of the binding of C-reactive protein to histones and chromatin. 319 19

alpha 1-Antitrypsin (AAT) has been purified from human plasma supernatant A (equivalent to COHN fraction II + III) by a large-scale chromatographic procedure involving anion-exchange adsorption on DEAE Sepharose CL-6B fast flow and size-exclusion chromatography on Sephacryl S-200. Before freeze-drying, the liquid concentrate was heat-treated at 60 degrees C for 10 h to reduce the risk of transmission of blood-born viral diseases. Using this procedure, AAT is recovered with 80-90% purity in 65-75% yield from supernatant A. The heterogeneity of AAT is preserved across the purification steps. In addition, purified AAT exhibits inhibitory activities against trypsin and elastase equivalent to that of the serum protein. The mean association rate constant for elastase was found as high as 2.15 X 10(5) M-1 s-1. Thus, purifying active AAT from supernatant A contributes to improving the availability of this protein which may be potentially useful in the treatment of hereditary emphysema.
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PMID:Biochemical and biological properties of an alpha 1-antitrypsin concentrate. 349 60

We have previously shown that human megakaryocyte colony-stimulating activity (Meg-CSA) is present in sera from patients with bone marrow megakaryocyte aplasia. In this report, we demonstrate that Meg-CSA is also present in sera from dogs rendered aplastic by 1000 rad total body irradiation. Canine serum Meg-CSA has activity comparable to human when assayed in plasma clot cultures containing human bone marrow mononuclear cells. Because of the uniform high potency and ready availability of aplastic canine sera, it was utilized initially for Meg-CSA purification. Sequential ammonium sulfate precipitation to approximately 80% saturation resulted in recovery of 59%-69% of the serum protein and of 75%-103% of the original serum Meg-CSA. The fraction precipitable between ammonium sulfate saturations of 0% and 44%-50% (fraction I) contained 53%-76% of the initial serum Meg-CSA and 25%-32% of the initial serum protein. This represents an enrichment of Meg-CSA specific activity by over 100%. The Meg-CSA eluted from Sephacryl S-300 in a single peak corresponding to a molecular weight of 175,000. This Meg-CSA peak also contained IgG, but the Meg-CSA did not bind to protein A-agarose. Meg-CSA was 90% inactivated by trypsin digestion for 4 h at 37 degrees C and by exposure to 5mM dithiothreitol for 2 h at room temperature. Exposure to either 6 M guanidine for 1 h at room temperature or 8 M urea for 1 h at 4 degrees C resulted in a 70% loss of Meg-CSA. At culture concentrations capable of stimulating maximal megakaryocyte colony formation, fraction I supported no colony growth by myeloid (CFU-GM) or late erythroid (CFU-E) human hematopoietic progenitor cells. Erythroid burst-promoting activity (BPA) was not detected in fraction I from two of three different aplastic canine sera tested. Therefore, Meg-CSA is functionally distinct from granulocyte-monocyte colony-stimulating factor (GM-CSF), erythropoietin, and BPA. The data indicate that serum Meg-CSA is a 175,000-dalton protein (megakaryocyte colony-stimulating factor, Meg-CSF) in which higher order structure and disulfide bonding are necessary for biologic activity. Partially purified Meg-CSF manifests functional specificity for the CFU-Meg hematopoietic progenitor cell.
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PMID:Human megakaryocyte colony-stimulating factor in sera from aplastic dogs: partial purification, characterization, and determination of hematopoietic cell lineage specificity. 387 46

Both synthesis and degradation of proteins are reduced in the hypothyroid state. The possible involvement of serum trypsin and chymotrypsin inhibitors has been studied in a family that, for four successive generations, had clinical or subclinical hypothyroidism. Increased trypsin- and chymotrypsin-inhibiting activity was demonstrated in the sera of the four clinically hypothyroid women. Cellulose acetate electrophoresis of the sera of these patients and of two other subclinical hypothyroid family members disclosed the distinct appearance of an additional fraction in the alpha 2-globulin zone. The serum protein electrophoretic pattern changes observed in familial hypothyroidism might be genetically determined. Such changes could precede the clinical onset of the disease, thus serving as a possible indicator of the hypothyroid state.
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PMID:Protease inhibitors in sera as possible indicators of familial hypothyroidism. 404 21

Studies were made on the isolation and identification of the Rickettsia typhi toxin-neutralizing factor (TNF) previously demonstrated in normal human serum. By means of various methods of separating serum proteins, such as filtration on Sephadex G-200, dextran precipitation, hydroxyapatite chromatography, and ultracentrifugation, TNF was found to be closely associated with purified serum beta-lipoprotein, although no serological relationship with this protein was demonstrated. Lipase as well as trypsin digestion of purified preparations of beta-lipoprotein destroyed the TN activity. No evidence was obtained for an association of TNF with the immunoglobulins or with any serum protein other than beta-lipoprotein. Further studies revealed that (i) serum specimens with TN titers of 1:1024 and others with titers of 1:8 or less contained the same concentration of beta-lipoprotein; (ii) purified preparations of beta-lipoprotein isolated from TNF positive and negative sera, and which had the same protein concentration, differed as much as 250-fold in TN titer; and (iii) the TN activity of a serum could be removed by absorption with antiserum to beta-lipoprotein from a positive donor, but not with antiserum to beta-lipoprotein from a negative donor.
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PMID:Murine typhus toxin: studies on identification of the neutralizing factor present in normal human serum. 462 56

Stalheim, O. H. V. (National Animal Disease Laboratory, Ames, Iowa). Leptospiral selection, growth, and virulence in synthetic medium. J. Bacteriol. 92:946-951. 1966.-The need for protein in leptospiral cultural medium may be circumvented by the use of strains which tolerate the lytic activity of polyoxyethylene sorbitan monooleate (Tween 80), a relatively nonlytic source of essential fatty acids. In an otherwise adequate medium, the primary function of a serum protein (bovine albumin fraction V) in the cultivation of Leptospira pomona was detoxification of fatty acids. Treatment to destroy or block end groups (amino, sulfhydryl, or hydroxyl) did not impair this function, but, after treatment with trypsin, albumin was inactive. Synthetic and derived peptides or polyvinylpyrrolidone did not substitute for albumin. L. pomona grew in medium with surface tension values of 44 to 58 dynes/cm(2); after growth, the values were increased slightly (5 to 8). The growth responses did not correlate with the surface tension of the medium, but they were in proportion to the concentration of Tween 80. Of six strains of L. pomona, five were transferred from medium containing rabbit serum and were subcultured in Tween synthetic medium (TSM) containing low, nonlytic concentrations (0.002%) of Tween 80. The poor antigenicity of L. pomona in carbon-limited TSM was associated with a deficiency of those carbonaceous cellular components which were extractable with 50% ethyl alcohol. After as few as four subcultures in TSM, L. pomona tolerated higher concentrations of Tween 80 (0.06% was optimal; MTSM). If grown on a shaker, the rate and amount of growth and the antigenicity of L. pomona in MTSM equaled that in medium supplemented with rabbit serum. After cultivation in MTSM, all of the five strains were avirulent when administered to hamsters, guinea pigs, and swine. They were still avirulent after three subcultures in complex media or after two serial passages in hamsters.
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PMID:Leptospiral selection, growth, and virulence in synthetic medium. 592 62


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