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)

1. To evaluate growth-promoting potencies of bovine insulin, bovine growth hormone (bGH), and recombinant human insulin like growth factor (rhIGF)-I and -II in the chicken, phenylalanine extraction from a synthetic serum-free culture medium into whole-embryos was measured. 2. The chicken embryos at 7 days of age were cultured in a rotatory embryo culture apparatus under a gas phase of 95% O2 and 5% CO2 at 37 degrees C for varying periods of time, and the change in phenylalanine contents in the medium was determined fluorimetrically. 3. Bovine insulin enhanced the phenylalanine extraction when added to the medium at 250 ng/ml whereas no significant change was observed below this concentration. 4. Intact bGH did not show any significant effect on the phenylalanine extraction in its intact form at the concentrations tested. However, bGH partially digested with trypsin increased the phenylalanine extraction. 5. The rhIGF-I enhanced the phenylalanine extraction significantly at 50 ng/ml with no significant increase below this level, whereas rhIGF-II showed no significant increase in phenylalanine extraction at any doses tested. 6. It was concluded that the whole-embryo culture was a quick and convenient system for searching physiologically active compounds that may have growth-promoting potency in the chicken.
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PMID:Effects of insulin, growth hormone, IGF-I and IGF-II on phenylalanine extraction in the chicken embryo cultured in vitro. 809 52

Confirmation of a protein's cysteine content and of its location within the amino acid sequence is crucial in investigating the structural integrity of recombinant proteins. A combination of thiol-specific chemistry and peptide mapping by reversed-phase microbore HPLC was used to confirm the presence and map the location of cysteine residues in the primary sequences of recombinant porcine growth hormone and human tumor necrosis factor alpha. Recombinant proteins were conjugated with a hydrophobic iodoacetamide derivative, dimethylaminoazo-benzene iodoacetamide, and digested with trypsin. The peptide fragments were separated on a C8 microbore reversed-phase column using a linear acetonitrile gradient. The peptides containing the cysteine residues were selectively identified by monitoring with a diode-array detector at 215 nm with the reference wavelength set at 450 nm. Cysteine-containing peptides could be readily distinguished as inverted "negative" peaks relative to the baseline and noncysteine-containing peptides. Isolated peptide fragments were then sequenced in order to confirm the location of the cysteines in the proteins. This approach offers the benefits of selectively and rapidly identifying, from a single chromatrophic step, the cysteine-containing peptides of proteins. Furthermore, the use of the labeling reagent renders the cysteine-containing peptides more hydrophobic, thereby making them easier to separate from noncysteine-containing peptides.
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PMID:Identification of cysteine-containing peptides during the peptide mapping of recombinant proteins. 825

A reverse-phase HPLC method for the analysis of tryptic digests of recombinant porcine growth hormone (pGH) has been developed and validated. Digestion was performed at 4 degrees C for a 20-hr period with TPCK-treated trypsin at a 1:20 (w/w) trypsin:pGH ratio. Gradient elution HPLC, using an Aquapore RP300 C8 column, was incorporated for separation of the digestion products and peak identification was carried out by mass spectrometry (MS). The digestion procedure and subsequent chromatography were linear in the initial concentration range of 4.55-45.46 microM (100 to 1000 micrograms/mL) pGH. The variability in the fragment retention times was low and the normalized peak area variability was less than 5% for all but three of the fragments. The utility of the trypsin digestion and chromatography procedures has been demonstrated by assessing chemical changes in pGH induced by incubation at elevated pH. Upon incubation of pGH in 0.2 M Tris buffer at pH 9 (ionic strength adjusted to 0.5 with NaCl) and 37 degrees C over a period of 400 hr, significant degradation in the regions corresponding to the digestion fragments T23-T25 (residues 181-182 linked by a disulfide bond to residues 184-191), T9 (residues 96-108), and T5-T18 (residues 43-64 linked by a disulfide bond to residues 158-166) was observed. The disappearance of the peaks corresponding to fragments T23-T25 and T9 both displayed apparent first-order degradation kinetics over the time period investigated with half-lives of 131 and 154 hr, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Validation of a peptide map for recombinant porcine growth hormone and application to stability assessment. 827 10

Murine ascites has been shown to contain a variety of growth promoting activities. In this study, we examined the effects of ascites fluid on the efficiency of hybridoma production and cell growth. SP2/0 mouse myeloma cells were injected into peritoneal cavities of mice and ascitic fluid was collected. Lymphocytes from mice immunized with porcine growth hormone (pGH) were fused with myeloma cells in a standard hybridization procedure. These cells were then dispensed in 96-well plates in medium containing either 2.5% ascites or 20% fetal calf serum (FCS) and cultured for few days. Supernatants from these cultures were collected and analyzed for anti-pGH antibodies. It was demonstrated that ascites-supplemented medium increased the efficiency in generating specific antibody-secreting hybridomas by 4-fold over FCS-supplemented medium. Furthermore, hybridoma cells were cultured in microtiter plate and found to proliferate in response to ascites in a dose dependent manner. This effect was abolished by prior digestion of ascites with trypsin, indicating its protein nature. B-lymphocyte related cytokines seemed less likely involved because antibodies to IL-4 and IL-6 failed to alter the stimulatory effect of ascites. Ascites was fractionated by FPLC using Superose 12 column and the active moiety was found to be a small m.w. peptide (< 1,000 dalton). Therefore, murine ascites is capable of substituting for conventional FCS in culture medium in the area of hybridoma technology.
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PMID:Effect of murine ascites on the ability of hybridoma cells to produce antibody and proliferate in vitro. 845 99

Membranes were prepared from tissues of the carp Ctenopharynogodon idellus including liver, kidney, intestine, adipose tissue, ovary, gill, heart, muscle and spleen. The carp liver and intestine membranes bound 125I-labeled bovine growth hormone and the binding could be displaced by cold bovine growth hormone. No changes in the ability to bind 125I-labeled bovine growth hormone occurred after treatment of the carp liver membrane with DNase, RNase, alpha-amylase and beta-glucosidase, suggesting that neither nucleic acids nor carbohydrates played an important part in the hepatic binding of growth hormone. Treatment of carp liver membranes with either chymotrypsin or trypsin produced a decrease in the growth hormone binding activity, indicating that the growth hormone receptor on carp liver membrane is a protein. Treatment of carp liver membranes with p-chloromercuribenzoate brought about a reduction in 125I-bGH binding. The inhibition could be reversed by dithioerythritol, suggesting the involvement of essential sulfhydryl group in bGH binding.
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PMID:Presence of growth hormone receptors in carp liver and intestine. 849 May 77

The amino acid sequence Asn-Gly has at pH 7 a tendency to induce deamidation of asparagine to aspartic acid via the formation of a cyclic imide. This imide opens up to yield Asp-Gly or the isoaspartic acid (isoAsp) form, isoAsp-Gly. Both isomers may be found in their L-form or D-form. Like Asn-Gly, the sequence Asp-Gly has a tendency for isomerization and racemization via the formation of a cyclic imide intermediate. When human growth hormone is digested with trypsin, one of the fragments is a heptapeptide (amino acid residues 128-134) containing the amino acid sequence Asp-Gly (amino acid residues 130 and 131). This heptapeptide, as well as stereoisomers and isoforms where L-Asp was replaced by D-Asp, L-isoAsp, D-isoAsp or the L-cyclic imide, respectively, has been synthesized and used as a standard to achieve separation of the five forms by capillary electrophoresis and by reverse-phase HPLC. Capillary electrophoresis analysis was performed in uncoated capillaries by the use of aspartic acid/cyclodextrin buffers at low pH. The elution order of the aspartic-acid-containing heptapeptides was D-Asp, L-Asp, L-isoAsp, D-isoAsp and L-cyclic imide. Reverse-phase HPLC analysis was performed on a C18 column by the use of a shallow acetonitrile gradient in trifluoroacetic acid/water. The elution order was D-isoasp, L-isoASp, L-Asp, D-Asp and L-cyclic imide. Human growth hormone samples were degraded by incubation at high temperature and analyzed for their potential content of isomerization and racemization products. Only L-forms of aspartic acid and isoaspartic acid of the heptapeptide fragment were found.
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PMID:Synthesis of stereoisomers and isoforms of a tryptic heptapeptide fragment of human growth hormone and analysis by reverse-phase HPLC and capillary electrophoresis. 863 46

Partial-thickness defects evolving in mature articular cartilage do not heal spontaneously. This type of defect was created in the articular cartilage of adult rabbits and Yucatan minipigs, and the effects of chondroitinase ABC or trypsin, fibrin clots, and mitogenic growth factors on the healing process were examined histologically at intervals ranging from one to forty-eight weeks. The effect of chondroitinase ABC or trypsin was examined initially. Articular cartilage contains macromolecules, including proteoglycans, which render the surfaces of this tissue, and of partial-thickness defects within it, antiadhesive. Chondroitinase ABC digests the glycosaminoglycan chains of cartilage proteoglycans, and trypsin degrades their core proteins. To test the hypothesis that mesenchymal cells may be prevented from adhering to and migrating over the surfaces of partial-thickness defects by proteoglycans, we removed a superficial layer of these macromolecules from the surface of the defect with use of one of these enzymes. The treatment evoked an increase in the coverage of the defect surface with mesenchymal cells; when combined with the local application of a mitogenic growth factor (basic fibroblast growth factor, transforming growth factor-beta 1, epidermal growth factor, insulin-like growth factor-1, or growth hormone), the coverage was more extensive but mesenchymal cells did not extend into and completely fill the volume of the defect. When the surface of the defect was treated with chondroitinase ABC and the cavity of the defect was filled with a fibrin clot to furnish a matrix or scaffolding for the migration of cells therein, there was migration and proliferation of cells throughout the volume of the defect but at a low population density. Mesenchymal cells remodeled the deposited fibrin matrix, which was replaced by a loose fibrous connective tissue. When defects that had been treated with chondroitinase ABC were filled with a fibrin clot containing a mitogenic growth factor, mesenchymal cells filled the entire cavity of the defect, and the density of the cells was greatly increased, particularly when transforming growth factor-beta 1 was used. Histological studies revealed a continuous layer of mesenchymal cells extending from the synovial membrane across the superficial tangential zone of normal articular cartilage into the defect, indicating that the cells that were recruited for the repair process were of synovial origin. At forty-eight weeks, the entire cavity of the defect remained filled with a fibrous connective tissue.
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PMID:Repair of partial-thickness defects in articular cartilage: cell recruitment from the synovial membrane. 864 29

Soluble forms of growth hormone receptors, growth hormone-binding proteins (GH-BPs), with molecular weights of 60 and 55kDa were found to be constitutively released from human IM-9 cells. The release of the GH-BPs was not inhibited by inhibitors of protein synthesis (cycloheximide) and transport (brefeldin A). Down-regulation by human growth hormone or trypsin pretreatment of surface growth hormone receptors abolished the GH-BP release, suggesting that cell-surface human growth hormone receptors are involved in the GH-BP release. Several inhibitors of serine-, thiol-, and acid-proteases did not affect the GH-BP release. EDTA efficiently blocked the GH-BP release. This inhibition by EDTA was restored by addition of Mg(2+) and Co(2+). These results suggest that human GH-BPs are constitutively released by proteolytic cleavage of cell-surface growth hormone receptors by a metalloprotease.
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PMID:Release of a soluble form of growth hormone receptors (growth hormone-binding proteins) from human IM-9 cells by proteolytic cleavage. 869 Jul 11

A new variant of human growth hormone was recently found [Pavlu, B. & Gellerfors, P. (1993) Bioseparation 3, 257-265]. We report here the identification and the structural determination of this variant. The variant, which is formed during the expression of human growth hormone in Escherichia coli, was found to be more hydrophobic than rhGH as judged by its prolonged elution time by hydrophobic interaction chromatography. The rhGH hydrophobic variant (rhGH-HV) was isolated and subjected to trypsin digestion and RP-HPLC analysis, resulting in an altered retention time of one single tryptic peptide as compared to the corresponding fragment of rhGH. This tryptic peptide constitutes the C-terminus (aa 179-191) of hGH and contains one of the two disulfide bridges in hGH, viz. Cys182-Cys189. Amino acid sequences and composition analyses of the tryptic peptide from rhGH-HV (Tv18-19) and the corresponding tryptic peptide from rhGH (T18+19) were identical. Electrospray mass spectrometry (ES MS) of Tv18+19 isolated from rhGH-HV revealed a monoisotopic mass increase of 32.7, as compared to T18+19 from rhGH. A synthetic Tv18+19 peptide having a trisulfide bridge between Cys182 and Cys189 showed identical fragment in ES/MS compared to Tv18+19 isolated from rhGH-HV, i.e. m/z 617.7 and 682.9. These fragments are formed through a unique cleavage in the trisulfide (Cys182-SSS-Cys189) bridge not found in the corresponding T18+19 disulfide peptide. Furthermore, the synthetic Tv18+19 co-eluted in RP-HPLC with Tv18+19 isolated from rhGH-HV. Two-dimensional NMR spectroscopy of the synthetic T18+19 and Tv18+19 peptides were performed. Using these data all protons were assigned. The major chemical shift changes (delta delta > 0.05 ppm) observed were for the beta-protons of Cys182 and Cys189 in Tv18+19 as compared to T18+19. CD spectroscopy data were also in agreement with the above results. Based on these physico-chemical data rhGH-HV has been structurally defined as a trisulfide variant of rhGH. The receptor binding properties of rhGH-HV was studied by a biosensor device, BIAcore. The binding capacity of rhGH-HV was similar to rhGH with a binding stoichiometry to the rhGHBP of 1:1.6 and 1:1.5, respectively, indicating that the trisulfide modification did not affect its receptor binding properties.
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PMID:Isolation and characterization of a trisulfide variant of recombinant human growth hormone formed during expression in Escherichia coli. 873 57

In this report, we describe the results of a rat pituitary cell culture experiment done on STS-65 in which the effect of cell feeding on the release of the six anterior pituitary hormones was studied. We found complex microgravity-related interactions between the frequency of cell feeding and the quantity and quality (i.e. biological activity) of some of the six hormones released in flight. Analyses of growth hormone (GH) released from cells into culture media on different mission days using gel filtration and ion exchange chromatography yielded qualitatively similar results between ground and flight samples. Lack of cell feeding resulted in extensive cell clumping in flight (but not ground) cultures. Vigorous fibroblast growth occurred in both ground and flight cultures fed 4 times. These results are interpreted within the context of autocrine and/or paracrine feedback interactions. Finally, the payload specialist successfully prepared a fresh trypsin solution in microgravity, detached the cells from their surface and reinserted them back into the culture chamber. These cells reattached and continued to release hormone in microgravity. In summary, this experiment shows that pituitary cells are microgravity sensitive and that coupled operations routinely associated with laboratory cell culture can also be accomplished in low gravity.
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PMID:Feeding frequency affects cultured rat pituitary cells in low gravity. 898 70


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