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)

Rats were fed raw soybeans or purified soybean proteinase inhibitors by tube to see whether they were able to produce inhibitor-resistant trypsin, as previously demonstrated in humans. Their duodenal chyme contained only 20-50% of the enzymatic activities of animals fed bovine serum albumin (BSA) as test protein. However, both tryptic and chymotryptic activities had considerable resistance to low- and high-molecular-weight inhibitors of serine proteinases. In particular, the tryptic activity demonstrated a high degree of inhibitor resistance. Human alpha 1-antitrypsin and lima bean inhibitor in amounts that inhibited bovine serum albumin-induced trypsin completely caused only 2-12% inhibition of the raw soybean-induced tryptic activity. The inhibitor-resistant tryptic and chymotryptic activities after raw soybean instillation might be caused by the Bowman-Birk and Kunitz trypsin inhibitors. The physiologic significance of an inhibitor-resistant trypsin might be to assure activation of other pancreatic proenzymes. The results of the present rat experiments confirm the previous findings of inhibitor-resistant trypsin in humans.
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PMID:Raw soy and purified proteinase inhibitors induce the appearance of inhibitor-resistant trypsin and chymotrypsin activities in Wistar rat duodenal juice. 200 5

1. A factor found in rabbit serum inhibits globin mRNA translation in vitro. 2. Inhibition of globin mRNA translation has been demonstrated in a cell-free rabbit reticulocyte lysate. 3. The inactivation of globin mRNA translation is not attributed to either serum albumin or ribonuclease activities. 4. Dialyzing the inhibitor for 24 hr at 4 degrees C does not result in the diminution of the inhibiting activity. However, the activity of the inhibitor is destroyed by heating to 70-80 degrees C for 5 min or by treatment with trypsin for 2 hr. 5. Ion exchange chromatography points to the inhibitor being a neutral protein, whereas, polyacrylamide gel electrophoresis reveals one major band with mol. wt 43 kDa. 6. The activity of the inhibiting material 3-fold greater in anemic serum than in normal serum. 7. These studies suggest that rabbit serum contains a protein inhibitor that may play a physiological role in regulating protein synthesis in red cells.
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PMID:An inhibitor(s) of globin mRNA translation in rabbit serum. 202 94

Human Sertoli cells in vitro secrete a factor that stimulates steroid biosynthesis in purified human and rat Leydig cells as well as in the MA-10 mouse tumor Leydig cell line. MA-10 cells were used as a bioassay system to follow the characterization and purification of the active principle in the conditioned medium of human Sertoli cells. The Leydig cell stimulatory factor is a thermo-labile and trypsin-sensitive protein retained onto 10,000 mol wt (MW) cut-off filters. The following scheme was used to purify the active protein: concentration by ammonium sulfate (80%) precipitation, followed by dialysis using molecularporous membrane tubing of MW cut-off 12,000-14,000, heparin-agarose, Concanavalin-A-Sepharose, and immobilized reactive textile dye affinity chromatography. Yellow 86 and green 19 dyes immobilized on agarose matrix were used. This procedure resulted in the rapid (less than 24-h) purification of a 79,000 +/- 6,082 (n = 3; under denaturating conditions) MW protein which stimulated Leydig cell steroid biosynthesis 25-fold at picomolar concentrations. The MW of the biologically active protein was further confirmed to be around 80,000 by gel filtration chromatography. This 80,000 MW human Sertoli cell-secreted protein (hSCSP-80) was shown to be different from human transferrin, human serum albumin, and rat testibumin. hSCSP-80, by modulating Leydig cell steroid biosynthesis, may play a significant role in the regulation of testicular function.
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PMID:Identification and purification of a human Sertoli cell-secreted protein (hSCSP-80) stimulating Leydig cell steroid biosynthesis. 202 54

A procedure for maintaining broiler adipocytes in culture was established and used to evaluate the effect of selected culture ingredients on glucagon-stimulated lipolysis. Adipocytes were isolated by collagenase and trypsin digestion of abdominal adipose tissue from 40- to 70-day-old broilers. Freshly isolated adipocytes did not exhibit glucagon-stimulated lipolysis. However, after 24 h in culture, lipolysis was stimulated maximally at doses of glucagon from 5 to 100 ng/mL with 50% stimulation occurring at .7 +/- .4 ng/mL. This responsiveness was maintained for an additional 24 h in culture. Inclusion of 2 or 5% chicken serum in the medium reduced (P less than or equal to .05) the responsiveness of the cells to glucagon. A 30% reduction (P less than or equal to .001) in responsiveness occurred when bovine serum albumin was removed from the medium. The results indicate that broiler adipocytes can be maintained in culture and that certain culture ingredients alter the responsiveness of the cells to glucagon.
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PMID:Glucagon-stimulated lipolysis of primary cultured broiler adipocytes. 202 37

Chlamydia trachomatis (L2) adhere to and infect chorionic membrane in vitro. Similarly, chlamydiae pre-exposed to either chorion homogenate, newborn calf serum or pure bovine serum albumin display a higher infectivity against mouse fibroblast cells in vitro. Polyacrylamide gel electrophoresis of the chorion homogenate displays a peptide band which co-migrates with albumin. Isolated chlamydiae stripped of protein with trypsin and exposed to albumin-containing solutions are precipitated by both anti-chlamydia and anti-albumin antibody. These findings suggest that albumin may selectively adhere to the surface of chlamydiae and serve an intermediary role in the infectious process.
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PMID:Albumin enhances chlamydial infectivity on human placental cells. 203 Jun 47

A protease inhibitor which is equally active on bovine and porcine trypsins was isolated in a homogenous form from jack bean (Canavalia ensiformis). The preparation with a molecular weight of 18 kDa was found to be a glycoprotein with a high half cysteine content. Isoleucine and tyrosine were found to be absent. The inhibitor was heat-stable and stable at pH 2.0 and 11.0. It was ten times less active on bovine alpha-chymotrypsin and pronase than on trypsin. It displayed weak action on subtilisin BPN, porcine elastase and pepsin. The inhibitor was most effective in blocking the total proteolytic, tryptic and chymotryptic activities of rabbit pancreatic preparation. The relative ratios of inhibitions of the three activities on rabbit, bovine and human systems were respectively 1250:100:1, 600:100:1 and 46:18:1. While different substrates (except denatured serum albumin) did not significantly alter the magnitude of inhibition of bovine trypsin, the extent of inhibition of bovine alpha-chymotrypsin by the jack bean inhibitor was highly dependent on the substrate used in the assay.
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PMID:Natural plant enzyme inhibitors: isolation and properties of a trypsin inhibitor from jack bean (Canavalia ensiformis). 207 40

The ability of native and chemically modified bovine serum albumin (BSA) to maintain normal pulmonary microvascular permeability was tested in "bloodless," fluorocarbon emulsion exchange transfused rats. Wet-to-dry weight ratios (W/D) of whole lung and morphometric estimates of the amount of ferritin transported to basement membrane were used to assess changes in water flux and macromolecular transport, respectively. Native and modified BSA in capillary walls were localized by immunogold techniques. Arginine residues of BSA were blocked with cyclohexanedione (CHD-BSA), and lysine residues were modified either by succinylation (Succ-BSA) or reductive methylation. Succinylation and CHD modification of BSA caused alterations in antigenicity and trypsin sensitivity; succinylation reduced the isoelectric point (pI). Whereas administration of either CHD-BSA or Succ-BSA increased the W/D, transport of ferritin to basement membrane was greater in the presence of Succ-BSA than CHD-BSA. By contrast, infusion of reductively methylated BSA in which modified lysines altered neither antigenicity nor pI, resulted in a W/D and amount of ferritin in basement membranes comparable to that of BSA. Binding of CHD-BSA and Succ-BSA to endothelial glycocalyx appeared to be reduced relative to native BSA and reductively methlyated BSA. The lowered pI of Succ-BSA may have contributed to its reduced binding; reductively methylated BSA with an unaltered pI was present in the glycocalyx. These data are consistent with a role for positively charged arginine residues in the interaction of albumin with the glycocalyx. The W/D of animals perfused with BSA was higher than those reported for rats perfused with complete rat serum proteins. This is consistent with the notion that serum factors, in addition to albumin, are required to maintain normal microvascular permeability.
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PMID:Interaction of native and chemically modified albumin with pulmonary microvascular endothelium. 210 71

Oxidant-induced injury is associated with breakdown of interstitial collagen and the accumulation of inflammatory cells in the lungs. In previous studies, we demonstrated that phagocyte accumulation is mediated, in part, by chemotactic factors generated from damaged collagen. To determine if alveolar macrophages also mediate the migration of polymorphonuclear leukocytes (PMN) into the lungs, we examined the release of chemotactic factors from alveolar macrophages treated with native or synthetic collagenous peptides. These included fragments of bovine collagen digested with bacterial collagenase (CG) or cyanogen bromide (CB) as well as small molecular weight synthetic polypeptides containing proline (Pro), glycine (Gly), and hydroxyproline (Hyp), the major amino acids that comprise collagen. We found a dose- and time-related generation of PMN chemotactic activity by collagen peptide-treated macrophages. The maximum activity was released 72 h after pretreatment of macrophages for 1 to 3 h with 0.1 to 1 microM CG-, CB-, or (Pro-Pro-Gly)5-peptides. The native peptides derived from CG-digested collagen were more active than synthetic peptides containing Pro and Gly. Neither trypsin digests of bovine serum albumin nor synthetic peptides containing Hyp stimulated chemotactic factor release from macrophages. The alveolar macrophage-derived chemotactic factor was found to lose activity when dialyzed and after heat or trypsin treatment. The release of PMN-activating factors by collagen peptide-treated macrophages was also examined. Alveolar macrophage-conditioned medium was found to stimulate PMN production of reactive oxygen intermediates as well as elastase and gelatinase.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Activation of neutrophils by factors released from alveolar macrophages stimulated with collagen-like polypeptides. 216 Feb 56

HBsAg is known to bind to human serum albumin polymerized by glutaraldehyde, human serum albumin has been found in preparations of HBsAg by several investigators. However, it is not yet known whether natural human serum albumin binds to hepatitis B virus under physiological conditions. We studied the binding between natural or recombinant HBsAg and monomeric human serum albumin by immunological, biochemical and biophysical methods. The binding capacity of 20-nm HBs spheres was variable but ranged up to six molecules HSA/sphere. A reversible binding site for human serum albumin was exclusively localized in the preS2 domain, whereas the S domain was inactive in vitro. Human serum albumin copurified with HBsAg of human origin during gel chromatography or sucrose-gradient centrifugation. This human serum albumin was monomeric in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The preS2-bound part of the human serum albumin could be removed from HBsAg by high-salt, such as CsCl centrifugation, but another part could only be removed by treatment with a disulfide cleaving reagent. Most of this covalently bound human serum albumin was retained at the HBsAg particle after complete cleavage of medium-sized HBs protein with trypsin. This indicates a second way in which albumin binds irreversible to cysteine(s) of the small HBs protein (SHBs, P24 and GP27).
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PMID:Interaction between hepatitis B surface proteins and monomeric human serum albumin. 216 67

The intracellular site of sphingomyelin (SM) synthesis was examined in subcellular fractions from rat liver using a radioactive ceramide analog N-([1-14C]hexanoyl)-D-erythro-sphingosine. This lipid readily transferred from a complex with bovine serum albumin to liver fractions without disrupting the membranes, and was metabolized to radioactive SM. To prevent degradation of the newly synthesized SM to ceramide, all experiments were performed in the presence of EDTA to minimize neutral sphingomyelinase activity and at neutral pH to minimize acid sphingomyelinase activity. An intact Golgi apparatus fraction gave an 85-98-fold enrichment of SM synthesis and a 58-83-fold enrichment of galactosyltransferase activity. Controlled trypsin digestion demonstrated that SM synthesis was localized to the lumen of intact Golgi apparatus vesicles. Although small amounts of SM synthesis were detected in plasma membrane and rough microsome fractions, after accounting for contamination by Golgi apparatus membranes, their combined activity contributed less than 13% of the total SM synthesis in rat liver. Subfractions of the Golgi apparatus were obtained and characterized by immunoblotting and biochemical assays using cis/medial (mannosidase II) and trans (sialyltransferase and galactosyltransferase) Golgi apparatus markers. The specific activity of SM synthesis was highest in enriched cis and medial fractions but far lower in a trans fraction. We conclude that SM synthesis in rat liver occurs predominantly in the cis and medial cisternae of the Golgi apparatus and not at the plasma membrane or endoplasmic reticulum as has been previously suggested.
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PMID:Sphingomyelin synthesis in rat liver occurs predominantly at the cis and medial cisternae of the Golgi apparatus. 218 69


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