Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00790 (PGA)
 2,475 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ribulose-diphosphate carboxylase from Thiobacillus novellus has been purified to hemogeneity as observed by polyacrylamide gel electrophoresis and U.V. light observation during sedimentation velocity analysis. The optimum pH for the enzyme with Tris-HCl buffers was about 8.2. Concentrations of this buffer in excess of 80 mM were inhibitory. The apparent Km for RuDP was about 14.8 muM with a Hill value of 1.5, for HCO3- the apparent Km was about 11.7 mM with an n value of 1.18 and for Mg2+ about 0.61 mM. The enzyme was specific for this cation. Relatively high concentrations of either Hg2+ or pCMB were required before significant inhibition was observed. Activity declined slowly during a 4-hr incubation period in either 3.0 M or 8.0 M urea. Incubation for 12 hrs resulted in complete loss of activity which was not prevented by 10 mM Mg2+ and was not reversed by dialysis and subsequent addition of 10 mM cysteine. Polyacrylamide gel electrophoresis revealed a loss of the major band and the appearance of 2 new bands. SDS polyacrylamide gel electrophoresis gave an average M.W. of 73500 +/- 2500 for the slower moving band and 12250 +/- 2500 for the faster moving. However, incubation in urea for up to 40 hrs revealed a decrease in the M.W. of the slower moving band to about 60000. The Ea for the enzyme was calculated to be about 18.85 kcal mole-1, with the possibility of a "break" between 40 and 50 degrees C. The Q10 was 3.07 between 20 and 30 degrees C whereas between 30 to 40 degrees C it was 3.31. Only phosphorylated compounds caused significant inhibition of enzyme activity. They included ADP, FDP, F6P, G6P, PEP, 6PG, 2-PGA, R1P, R5P, and Ru5p.
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PMID:Properties and regulation of ribulose diphosphate carboxylase from Thiobacillus novellus. 24 94

Collagen synthesis was studied in monolayer cultures of rabbit corneal endothelial cells by following [14C]proline and [3H]glucosamine or [3H]fucose incorporation into a fraction enriched for collagen and its precursor molecules. Sodium dodecyl sulfate gel electrophoresis of this fraction showed that it consisted of a high-molecular-weight (greater than 300,000 daltons) polypeptide. This component was collagenase sensitive and, in the presence of dithiothreitol, gave rise to two polypeptides of the apparent molecular weights of 200,000 and 160,000 daltons. Pepsin digestion of this material destroyed all the high-molecular-weight material and gave rise to a single collagenase-sensitive component of an apparent molecular weight of 115,000 daltons. This 115,000 dalton material is similar to previously observed basement membrane collagens, and the 160,000 and 200,000 dalton components are probably precursor chains of basement membrane collagen. The very-high-molecular-weight material (greater than 300,000 daltons) may represent a disulfide-linked complex of these precursor chains. DEAE-cellulose column chromatography confirmed the presence of a single procollagen species distinct from the collagen fraction. Amino acid analysis of collagen and procollagen fractions showed a decreased hydroxyproline value as compared with previously reported basement membrane collagens or collagen precursors.
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PMID:Biochemical characterization of procollagen-collagen synthesized by rabbit corneal endothelial cells in culture. 75 87

Human nucleus pulposus and annulus fibrosus, obtained at autopsy from patients 7-30 years of age, were extracted with 2 M guanidine-HCl (pH 5.82) to remove proteoglycans, then stirred with pepsin in 0.5 M acetic acid, followed by three 24-h extractions with 1 M NaCl (pH 7.5) and one 24-h extraction with 2 M KSCN (potassium thiocyanate) (pH 7.2). Pepsin and NaCl solubilized an average of about 30% of nucleus pulposus collagen and 18% of annulus fibrosus collagen. KSCN extracted a further 34% of nucleus pulposus collagen and only 4% of annulus fibrosus collagen. CM-cellulose chromatography of nucleus and annulus collagen purified from the pepsin, NaCl and KSCN supernatants consistently revealed only one peak, always appearing slightly ahead of the alpha1 position for rat tail tendon type I collagen. Polyacrylamide and SDS-gel electrophoresis consistently revealed only one band with the mobility of alpha1 chains. Amino acid composition of collagen from nucleus and annulus is comparable to those of mammalian and avian cartilage type II collagen, and distinctly different from those of rat tail tendonand guinea pig skin type I collagens. Periodate oxidation of nucleus and annulus collagens showed that 81% and 67%, respectively, of the hydroxylysine residues survive treatment, compared to 71% for bovine articular cartilage collagen and 17% for guinea pig skin collagen. Total hexose analysis revealed 1.8 muM and 2.0 muM hexose per muM periodate-stable hydroxylysine in nucleus and annulus collagens, respectively. Ion exchange chromatography showed the presence of glucose and galactose in a ratio of 0.92:1 in nucleas collagen and 1.07:1 in annulus collagen. Pepsin-solubilized, NaCl-extracted collagen from nucleus and annulus formed native-type fibrils in vitro. The banding patterns of ATP-induced segment-long-spacing precipitates of nucleus and annulus collagens were identical to each other and indistinguishable from those of cartilage (type II) collagen, but distinctly different from those of rat tail tendon (type I) collagen. These data suggest that the collagen which can be extracted after limited pepsin attack of human nucleus and annulus is of the form [alpha1 (II)]3.
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PMID:Pepsin-solubilized collagen of human nucleus pulposus and annulus fibrosus. 78 25

To understand more directly the tissue defect in osteogenesis imperfecta (OI), bone matrix was analyzed from an infant with lethal OI (type II) of defined mutation (collagen alpha 2(I)Gly580-->Asp). Pepsin-solubilized alpha 1(I) and alpha 2(I) chains and derived CNBr-peptides migrated more slowly on sodium dodecyl sulfate-polyacrylamide gel electrophoresis compared with normal human controls. The peptide alpha 2(I)CB3,5, predicted to contain the mutation site, ran as a retarded doublet band and was purified by high performance liquid chromatography and digested with V8 protease. Two peptides with amino-terminal sequences beginning at residue 576 of the alpha 2(I) chain were isolated. One had the normal sequence. The other differed in that aspartic acid replaced glycine at residue 580 as predicted from cDNA analysis, and in having an unhydroxylated proline at residue 579. From yields on microsequencing and the relative intensities of the two forms of alpha 2(I)CB3,5 on SDS-polyacrylamide gel electrophoresis, the ratio of mutant to normal alpha 2(I) chains in the infant's bone matrix was 0.7/1. Although the effects of an efficient incorporation of mutant chains on the properties of the bone matrix are unknown, it may be that in this OI case the tissue abnormalities result more from the presence of mutant protein than from an underexpression of matrix.
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PMID:Incorporation of type I collagen molecules that contain a mutant alpha 2(I) chain (Gly580-->Asp) into bone matrix in a lethal case of osteogenesis imperfecta. 138 13

Selection of ideal laser parameters for tissue welding is inhibited by poor understanding of the mechanism. We investigated structural changes in collagen molecules extracted from rat tail tendon (> 90% type I collagen) after tissue welding using an 808 nm diode laser and indocyanine green dye applied to the weld site. Mobility patterns on SDS-PAGE were identical in the lasered and untreated tendon extracts with urea or acetic acid. Pepsin incubation after acetic acid extraction revealed a reduction of collagen alpha and beta bands in lasered compared with untreated specimens. Circular dichroism studies of rat tail tendon showed absence of helical structure in collagen from lasered tendon. No evidence for covalent bonding was present in laser-treated tissues. Collagen molecules are denatured by the laser wavelength and parameters used in this study. No significant amount of helical structure is regenerated on cooling. We conclude that non-covalent interactions between denatured collagen molecules may be responsible for the creation of tissue welding.
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PMID:Changes in type I collagen following laser welding. 140 2

Extract obtained by ultrasonic disruption of Helicobacter pylori bacteria contained a protein with subunit molecular mass of 25 kD which bound antibodies in sera from patients with H. pylori-associated disease. The protein was purified by gel permeation and elution from SDS-polyacrylamide gel slices, and was used to raise an anti-25-kD protein-specific rabbit serum. Using the antiserum in experiments, the results indicated the following: The protein exists as covalently linked dimers (45 kD) of the 25-kD subunits. Variable numbers of non-covalently linked copies of the dimers make up the native protein. The protein was susceptible to digestion by papain, pronase, and trypsin. Pepsin cleaved off a fragment of approximately 2 kD. A small share of the protein was exposed at the bacterial cell surface, the greatest share being localized internally. The protein was not secreted and it was probably not an integral part of the outer membrane. It was produced in variable quantity by all of 11 H. pylori strains tested and was a major protein in some strains. A cross-reacting protein with subunit size of 25 kD was also produced by Campylobacter jejuni strains, but not by any of a variety of other bacteria. Since both H. pylori and C. jejuni infection occur with a high frequency. the cross-reacting 25-kD protein may interfere unfavourably with the diagnostic specificity of serological tests for infection caused by these bacteria.
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PMID:Characterization of a 25,000-dalton Helicobacter pylori protein, cross-reacting with a Campylobacter jejuni protein. 158 85

Cyclopentenone prostaglandins (PGs) such as delta 12-PGJ2 and PGA are potent inducers of growth inhibition in a variety of cultured cells, including epidermal cells. These PGs are actively transported into cells by a specific carrier on cell membrane and accumulate in cell nuclei with binding to nuclear protein. To clarify the mechanism of cytotoxicity of these PGs in epidermal cells, we examined the effects of delta 12-PGJ2 on protein synthesis and cytoskeleton in the PAM 212 transformed mouse epidermal cell line. Cycloheximide at 1 microgram/ml culture medium exhibited a protective effect on cell growth inhibition of PAM 212 cells by delta 12-PGJ2. The analysis of cell lysate protein patterns by SDS-polyacrylamide gel electrophoresis revealed that 12-h incubation with delta 12-PGJ2 increased the amount of 70 kD protein in PAM 212 cells. The amount of 70 kD protein in delta 12-PGJ2-treated cells was markedly decreased by cotreatment with cycloheximide. This 70 kD protein was also induced in PAM 212 cells with treatment at 43 degrees C for 90 min, indicating that this synthesized protein belongs to the heat shock protein. The addition of delta 12-PGJ2 to confluent PAM 212 cells resulted in the disappearance of action filament, as visualized by fluorescent labeled phallacidine, but in contrast, keratin filament appeared to be intact during 12-h incubation with delta 12-PGJ2 at a concentration of 5 micrograms/ml culture medium. These results suggest that the cytotoxicity of cyclopentenone PGs is at least in part due to induction of the synthesis of some protein(s), probably one of the heat shock proteins, and the damage to the actin filament in transformed cultured epidermal cells.
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PMID:Effects of cytotoxic prostaglandin, delta 12-PGJ2 on protein synthesis and cytoskeleton in transformed epidermal cells in culture. 169 39

The biosynthesis of type I, type V and type VI collagens was studied by incubation of calf corneas in vitro with [3H]proline as a marker. Pepsin-solubilized collagen types were isolated by salt fractionation and quantified by SDS/PAGE. Expressed as proportions of the total hydroxyproline solubilized, corneal stroma comprised 75% type I, 8% type V and 17% type VI collagen. The rates of [3H]proline incorporation, linear up to 24 h for each collagen type, were highest for type VI collagen and lowest for type I collagen. From pulse-chase experiments, the calculated apparent half-lives for types I, V and VI collagens were 36 h, 10 h and 6 h respectively.
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PMID:Relative rates of biosynthesis of collagen type I, type V and type VI in calf cornea. 200 24

Type X collagen was extracted with 1 M-NaCl and 10 mM-dithiothreitol at neutral pH from fetal-bovine growth cartilage and purified to homogeneity by using f.p.l.c. gel filtration on a Superose 12 column, followed by ion-exchange chromatography on a Mono Q column. The purified protein migrates in SDS/polyacrylamide gels with an apparent Mr of 58,000 under reducing conditions and as a high-Mr oligomer in its unreduced form. The amino acid composition is similar to the published composition of chick type X collagen. Pepsin digestion at 4 degrees C decreases the Mr of the monomer to 43,000; purified bacterial collagenase digests most of the molecule, leaving a non-collagenous domain of apparent Mr 15,000, which probably represents the C-terminal globular domain. The IgG fraction from a rabbit antiserum raised against purified bovine type X collagen was specific for this collagen by the criteria of e.l.i.s.a. and immunoblotting after immunoabsorption with collagen types I, II, IX and XI. Immunofluorescence localization of type X collagen in sections of fetal-bovine and human cartilage was possible after acetone fixation of sections and hyaluronidase treatment. Type X collagen was restricted to the zone of hypertrophic and calcified cartilage inside the bone spicules of the growth plate.
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PMID:Isolation of bovine type X collagen and immunolocalization in growth-plate cartilage. 240 43

L-Aspartate and L-serine were found to undergo amino acid racemization in brain myelin basic protein (MBP) of aging humans. The observed racemization was different in each chromatographically purified MBP isoform. Pepsin digestion of MBP produced three peptides, each of which exhibited different degrees of racemization of the same amino acids. MBP isolated by the same method from rat and guinea pig brain showed little accumulation of D-amino acids. Total MBP isolated from SDS-polyacrylamide disc gel electrophoresis of total human myelin proteins (delipidated myelin) was racemized to the same extent as purified MBP, indicating that the racemization observed was not an artifact of the isolation procedure. Myelin proteolipid protein from the same gel was racemized approximately half as much as MBP. The age and environment of the aspartates and serines in myelin proteins may strongly affect their observed racemizations.
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PMID:Differential racemization of aspartate and serine in human myelin basic protein. 244 3


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