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)

Two pepsins (A and B) were purified from the stomach of pectoral rattail (Coryphaenoides pectoralis) by acidification, ammonium sulfate precipitation, gel filtration chromatography and anion exchange chromatography to obtain a single band on native-PAGE and SDS-PAGE. The purities of pepsin A and B were increased to 7.1- and 13.0-fold with approximately 5.7% and 2.2% yield, respectively. Pepsin A and B had the apparent molecular weights of 35 and 31 kDa, respectively, when analyzed using SDS-PAGE and Sephacryl S-200 gel filtration. Pepsin A and B showed maximal activity at pH 3.0 and 3.5, respectively, and had the same optimal temperature at 45 degrees C using hemoglobin as a substrate. Both pepsin A and B were stable in the pH range of 2.0-6.0 but were unstable at the temperatures greater than 40 degrees C. Activity of both pepsins was inhibited by pepstatin A and was activated by divalent cations, indicating pepsin characteristics. Activities of both pepsins continuously decreased as NaCl concentration increased (0-30%). The enzymes had high affinity and activity toward hemoglobin with Km and Kcat values of 98-152 microM and 32-50 S(-1), respectively. Purified pepsins generally showed the similar characteristics to other fish pepsins.
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PMID:Purification and characterization of two pepsins from the stomach of pectoral rattail (Coryphaenoides pectoralis). 1749 57

Prostaglandins with cyclopentenone structure (cyPG) display potent antiproliferative actions that have elicited their study as potential anticancer agents. Several natural and synthetic analogs of the cyPG prostaglandin A(1) (PGA(1)) have proven antitumoral efficacy in cancer cell lines and animal models. In addition, PGA(1) has been used as an inhibitor of transcription factor NF-kappaB-mediated processes, including inflammatory gene expression and viral replication. An important determinant for these effects is the ability of cyPG to form Michael adducts with free thiol groups. The chemical nature of this interaction implies that PGA(1) could covalently modify cysteine residues in a large number of cellular proteins potentially involved in its beneficial effects. However, only a few targets of PGA(1) have been identified. In previous work, we have observed that a biotinylated analog of PGA(1) that retains the cyclopentenone moiety (PGA(1)-B) binds to multiple targets in fibroblasts. Here, we have addressed the identification of these targets through a proteomic approach. Cell fractionation followed by avidin affinity chromatography yielded a fraction enriched in proteins modified by PGA(1)-B. Analysis of this fraction by SDS-PAGE and LC-MS/MS allowed the identification of the chaperone Hsp90, elongation and initiation factors for protein synthesis and cytoskeletal proteins including actin, tubulin and vimentin. Furthermore, we have characterized the modification of vimentin both in vitro and in intact cells. Our observations indicate that cysteine 328 is the main site for PGA(1) addition. These results may contribute to a better understanding of the mechanism of action of PGA(1) and the potential of cyPG-based therapeutic strategies.
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PMID:Study of protein targets for covalent modification by the antitumoral and anti-inflammatory prostaglandin PGA1: focus on vimentin. 1796 May 81

It is suggested that patients with oral allergy syndrome (OAS) respond to pepsin-sensitive allergens, and systemic reactors identify pepsin-resistant allergens. We sought to assess the digestibility of kiwifruit proteins in simulated gastric fluid (SGF), and to compare the immunogenicity of the digests in patients with isolated oral and systemic reactions to kiwifruit. In addition, the effect of pH on digestibility of kiwifruit proteins was investigated. The in vitro resistance of kiwifruit proteins to digestion was determined using SGF. G-immunoglobulin (IgE) binding to digested proteins was investigated by Western blotting using sera from children and adults (aged 5-72 yr) with systemic reactions and patients with isolated oral symptoms. To determine whether pH conditions influence digestion of kiwifruit extracts, digestion at pHs 1.5-7 were compared by SDS-PAGE. Patients with systemic reactions showed IgE binding to digestion-resistant allergens, but patients with oral symptoms reacted only to digestion-labile allergens. An increase in pH from 1.5 to 2.5 significantly reduced pepsin breakdown of kiwifruit allergens. Immunoreactive digested protein fragments were detectable by immunoblot but not Coomassie stain. This study confirms a difference in the lability of food allergens recognized by patients with systemic reactions and those with OAS. Pepsin digestion of kiwifruit proteins was impaired by hypoacidic conditions suggesting that patients with hypoacidic gastric conditions are at increased risk of systemic absorption of allergens. The data indicate that commonly used methods for predicting allergenicity of novel proteins using Coomassie stains may be flawed.
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PMID:The effect of digestion and pH on the allergenicity of kiwifruit proteins. 1808 17

Pepsin-soluble collagen (PSC) was extracted from fish scale of grass carp and was analyzed by SDS-PAGE, which confirmed that PSC are typical type I collagen and reach electrophoretic purity. Effect of temperature on the secondary structure of collagen was studied by FTIR, Raman and CD. FTIR indicated that the fish scale PSC had typically characteristic absorptions of collagen, and 1659, 1552 and 1238 cm(-1) were assigned to be amide I, II and III respectively. When the temperature increased, amide A and amide B shifted to low frequency, the absorption of 1658 cm(-1) split into several absorption peaks, the absorption at 1552 cm(-1) had a slight red-shift followed by a distinct blue-shift, and the frequency of 1238 cm(-1) declined. Raman spectra showed that the absorptions of amide I, amide II and amide III appeared at 1669, 1557 and 1245 cm(-1) respectively, which were higher than those in FTIR spectra. Furthermore, the characteristic absorptions of proline at 921 and 855 cm(-1) only appeared in Raman spectra. CD spectra demonstrated a rotatory maximum at 221.6 nm and a negative peak at 204.4 nm of PSC solution, which were typical spectral characteristics of the collagen triple helix structure. The structure changes of the lyophilized PSC appeared mainly between 35 and 60 degrees C in FTIR and Raman spectra, yet CD spectra demonstrated that the configurational changes of PSC in acidic solution appeared in the range of 20 to 35 degrees C, indicating that the lyophilized PSC was more stable than the acidic solution of PSC.
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PMID:[Effect of temperature on the secondary structure of fish scale collagen]. 1830 75

Alkaline pectate lyase (PL) from recombinant strain E. coli JM109 (pHsh PL) was purified by a three-step process including (NH4)2SO4 precipitation followed by dialysis and chromatography. The purified enzyme appeared homologous on SDS-PAGE. The specific activity of the purified enzyme reached 1079 U/mg. The optimal pH and temperature were in the ranges of pH 9.0 to 10.0 and 50 degrees C to 66 degrees C. The enzyme was preferable in optimal pH range in enzymatic retting of flax. Enzyme activity slightly increased in the presence of Mg2+ ion, whereas decreased in the presence of other ions, especially Fe2+. The K(m) of the purified enzyme for polygalacturonic acid was 20.93 mg/L, the V(max) for polygalacturonic acid hydrolysis was 105.3 micromol of unsaturated products per min and Ea was 21.74 kJ/mol. The results of the decay constant (k(d)) analysis on condition of PL bonding polygalacturonic acid (k(d) = 0.02 min(-1)) and PL without polygalacturonic acid (k(d) = 0.0342 min(-1)) showed the substrate was helpful to decrease thermal inactivation of PL. The products (unsaturated oligomers) from polygalacturonic acid degraded by PL were analyzed by electrospray ionization mass spectrometry(ESI-MS). The following data were obtained: ESI-MS m/z, 350.82 (unsaturated bigalacturonic acid, uG2), 527.04 (unsaturated trigalacturonic acid, uG3). However, m/z 175 (unsaturated galacturonic acid, uGI) was not found. These results indicate that the final PGA degradation products was a mixture of unsaturated oligo-galacturonides including uG3 and uG2 except for uG1. It suggests that the recombinant PL cannot degrade uG3 and uG2.
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PMID:[Properties of alkaline pectate lyase from recombinant strain E. coli JM109 (pHsh PL)]. 1833 88

Pepsin-solubilized collagen (PSC) was conjugated with carboxymethyl dextran (CMD) using cyanogen bromide to obtain a PSC-CMD film having improved physical properties, physiological properties, and cell affinity. The conjugation was confirmed by the loss of the alpha- and beta-subunit chains and the polymerized band on SDS-PAGE, and by a decrease in the isoelectric point to 3.2. PSC-CMD had a large polymerized structure with the 6 PSC and 228 CMD molecules. PSC-CMD was readily soluble in water, reconstructed a matrix with a less-ordered structure and a characteristic morphological shape, and lost platelet aggregation-inducing ability. The PSC-CMD film, cross-linked by ultraviolet irradiation, exhibited reduced solubility, moderate water vapor permeability, and increased flexibility. PSC-CMD coatings exhibited good cell attachment and growth for fibroblasts and vein endothrical cells.
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PMID:Polymerized structure and improved physical and biochemical material properties of carboxymethyl dextran-conjugated collagen. 1854 95

Pepsin from the stomach of albacore tuna, skipjack tuna, and tongol tuna was characterized. Pepsin from all tuna species showed maximal activity at pH 2.0 and 50 degrees C when hemoglobin was used as a substrate. Among the stomach extract of all species tested, that of albacore tuna showed the highest activity (40.55 units/g tissue) (P < 0.05). Substrate-Native-PAGE revealed that pepsin from albacore tuna and tongol tuna consisted of 2 isoforms, whereas pepsin from skipjack tuna had only 1 form. The activity was completely inhibited by pepstatin A, while EDTA (ethylenediaminetetraacetic acid), SBTI (soybean trypsin inhibitor), and E-64 (1-(L-trans-epoxysuccinyl-leucylamino)-4-guanidinobutane) exhibited negligible effect. The activity was strongly inhibited by SDS (sodium dodecyl sulfate) (0.05% to 0.1%, w/v). Cysteine (5 to 50 mM) also showed an inhibitory effect in a concentration dependent manner. ATP, molybdate, NaCl, MgCl(2), and CaCl(2) had no impact on the activity. When tuna pepsin (10 units/g defatted skin) was used for collagen extraction from the skin of threadfin bream for 12 h, the yield of collagen increased by 1.84- to 2.32-fold and albacore pepsin showed the comparable extraction efficacy to porcine pepsin. The yield generally increased with increasing extraction time (P < 0.05). All collagen obtained with the aid of tuna pepsin showed similar protein patterns compared with those found in acid-solubilized collagen. Nevertheless, pepsin from skipjack tuna caused the degradation of alpha and beta components. All collagens were classified as type I with large portion of beta-chain. However, proteins with molecular weight (MW) greater than 200 kDa were abundant in acid-solubilized collagen.
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PMID:Tuna pepsin: characteristics and its use for collagen extraction from the skin of threadfin bream (Nemipterus spp.). 1857 87

Many recognition events important in biology are mediated via multivalent interactions between relevant oligosaccharides and multiple saccharide receptors present on lectins, viruses, toxins, and cell surfaces. Because of the important role played by protein-carbohydrate interactions in these pathogenic recognition events and in other human diseases, considerable effort has been devoted toward the development of multivalent polymeric ligands for carbohydrate-binding proteins. In this work, we report the synthesis of new polypeptide-based glycopolymers produced via a combination of protein engineering and chemical methods. These methodologies permit control over the number and the spacing of saccharides on the scaffold, as well as the conformation of the polymer backbone, and allow a more purposeful design of polymers for manipulation of multivalent binding events. Two families of galactose-bearing glycopolypeptides with random coil conformations, [(AG)(3)PEG](y) (y = 10 and 16) and {[(AG)(2)PSG](2)[(AG)(2)PEG][(AG)(2)PSG](2)}(y) (y = 6), have been synthesized. The carboxylic acid functionality of the glutamic acid residues allowed subsequent modification with amino-saccharides to yield the desired glycopolypeptides; selective placement of the glutamic acid group permitted investigation of the effects of multivalency and saccharide spacing on toxin inhibition. In addition, a family of galactose-functionalized PGA-based glycopolymers of varying molecular weights was also synthesized to compare the effects of backbone flexibility and hydrodynamic volume, relative to the recombinant glycopolypeptides, on toxin inhibition. Glycopolypeptides were characterized via (1)H NMR, MALDI-TOF mass spectrometry, SDS-PAGE analysis, and spectrophotometric assays. They were tested as inhibitors of the binding of the cholera toxin B subunit via direct enzyme-linked assays. The data from these experiments confirm the relevance of appropriate saccharide spacing on controlling the binding event and also indicate the influence of chain extension in improving inhibition.
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PMID:Effects of Saccharide Spacing and Chain Extension on Toxin Inhibition by Glycopolypeptides of Well-Defined Architecture. 1916 74

The present work describes the purification and characterization of a novel extracellular polygalacturonase, PGase I, produced by Pycnoporus sanguineus when grown on citrus fruit pectin. This substrate gave enhanced enzyme production as compared to sucrose and lactose. PGase I is an exocellular enzyme releasing galacturonic acid as its principal hydrolysis product as determined by TLC and orcinol-sulphuric acid staining. Its capacity to hydrolyze digalacturonate identified PGase I as an exo-polygalacturonase. SDS-PAGE showed that PGase I is an N-glycosidated monomer. The enzyme has a molecular mass of 42kDa, optimum pH 4.8 and stability between pH 3.8 and 8.0. A temperature optimum was observed at 50-60 degrees C, with some enzyme activity retained up to 80 degrees C. Its activation energy was 5.352calmol(-1). PGase I showed a higher affinity towards PGA than citric pectin (Km=0.55+/-0.02 and 0.72+/-0.02mgml(-1), respectively). Consequently, PGase I is an exo-PGase, EC 3.2.1.82.
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PMID:Purification and characterization of an exo-polygalacturonase from Pycnoporus sanguineus. 1978 42

The following experimental results have been obtained. 1. Native egg albumin treated with iodine and then denatured no longer gives a nitroprusside test or reduces dilute ferricyanide in neutral Duponol PC solution. 2. More iodine is needed to abolish the ferricyanide reduction if the reaction between native egg albumin and iodine is carried out at pH 6.8 than if the reaction is carried out at pH 3.2. At pH 6.8 iodine reacts with tyrosine as well as with cysteine. 3. Cysteine and tryptophane are the only amino acids with reducing groups which are known to react with dilute iodine at pH 3.2 The reducing power of cysteine is abolished by the reaction with iodine, whereas the reducing power of tryptophane remains intact. Pepsin and chymotrypsinogen which contain tryptophane but not cysteine, do not react at all with dilute iodine at pH 3.2. 4. Native egg albumin treated with iodoacetamide at pH 9.0 and then denatured by Duponol PC reduces only 60 per cent as much dilute ferricyanide as egg albumin which has not been treated with iodoacetamide. 5. The SH group is the only protein reducing group which is known to react with iodoacetamide. The simplest explanation of the new observation that the SH groups of egg albumin can be modified by reactions with the native form of the protein is that the native egg albumin has free and accessible but relatively unreactive SH groups which can react with iodine and iodoacetamide despite the fact that they do not react with ferricyanide, porphyrindin, or nitroprusside. Preliminary experiments suggested by the results with egg albumin indicate that the tobacco mosaic virus is modified by iodine at pH 2.8 without being inactivated and that the tobacco mosaic and rabbit papilloma viruses are not inactivated by iodoacetamide at pH 8.0.
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PMID:THE REACTIONS OF IODINE AND IODOACETAMIDE WITH NATIVE EGG ALBUMIN. 1987 58


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