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)

Prostaglandins are analogs of the parent 20 carbon prostanoic acid. They are divided into 4 series: PGE; PGF; PGA; PGB, according to the presence of functionalities in the cyclopentane structure. Biosynthesis of prostaglandins were first independently reported by Bergstrom et.al. and van Dorp et.al. who showed that certain w-6-unsaturated fatty acids were biological precursors of prostaglandins. Later, various investigators reported the biosynthesis of prostaglandins of the different series. The 2 most widely used routes of prostaglandins synthesis are 1) the Corey cyclopentyl-lactone route, and 2) the bicyclohexane route. The synthesis is divided into 1) naturally occuring primary prostaglandins and 2) the prostaglandin analogs and derived prostaglandins. Because of the general instability of natural prostaglandins in the basic and acidic milieu, various preparations of prostaglandins and chemically stable dosage forms have been developed. Various methods used in analyzing prostaglandins include: 1) TLC; 2) GLC; 3) spectral methods; 4) radioimmunoassay; and 5) enzymatic assay. In vitro and in vivo studies on the metabolism and catabolism of various prostaglandins showed that they are rapidly metabolized in various animal systems and humans. The major routes for this metabolic transformation are: 1) oxidation of the secondary C15 hydroxy group; 2) reduction of the C13 double bond; 3) B-oxidation; 4) w-hydroxylation; and 5) w-oxidation. Prostaglandins produce a wide range of biological effects on animal and human systems (the reproductive; gastrointestinal; respiratory; and cardiovascular systems). The biological actions of prostaglandins on animal and human reproductive tissue vary depending on the particular prostaglandin studied and hormonal state of the tissue. Certain prostaglandins can decrease the tonus, frequency, and amplitude of spontaneous contractions of human uterine strips while other prostaglandins can cause contraction of isolated myometrial strips. Prostaglandins are widely used in labor induction; induction of therapeutic abortion; and fertility control. Prostaglandins have also been found to either increase or decrease cyclic AMP; inhibit ADP-induced platelet aggregation; lower blood pressure in animals; affect lipid and carbohydrate metabolism, and prevent adjuvant arthritis.
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PMID:Prostaglandins. 456 72

1. For a few weeks, immediately post-natally, the abomasum of the ruminant stomach can be regarded as the analogue of the simple stomach for at this time food passes directly to the abomasum because of closure of the oesophageal groove.2. Using standard fractional and serial test meal techniques discussed by Hunt (1956) and adapted for use in the calf, abomasal emptying, acid and pepsin secretion have been examined. Phenol red was used as a marker to measure volume changes of the test meal.3. Abomasal emptying is exponential in character whether large or small volumes of fluid are instilled into the abomasum. The initial and end phase of emptying shows variable rates between animals.4. Glucose and lactose solutions inhibit abomasal emptying as well as acid production.5. Sodium chloride and sodium bicarbonate of low concentration, near isotonic with blood plasma, stimulate abomasal emptying but the bicarbonate is most effective. Hypertonic solutions of these salts inhibit abomasal emptying.6. Pepsin secretion in the abomasum of the calf is not affected by test meals of glucose, lactose, sodium chloride or sodium bicarbonate.7. These results shows a great similarity between the physiology of the abomasum of the milk-fed calf and the simple stomach. This suggests that the same duodenal receptors, discussed by Hunt & Knox (1968), which control gastric movement in man are also effective in controlling gastric emptying in the milk-fed calf.
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PMID:Gastric emptying and secretion in the milk-fed calf. 456 10

1. The abomasum of the milk-fed calf has been examined using an adaptation of the Serial Test Meal method devised by Hunt & Spurrell (1951). The emptying process, acid secretion and pepsin secretion were studied.2. Using serial test meals of simple solutions instilled into the abomasum via a cannula, our investigation leaves no doubt that the osmolarity of the abomasal contents significantly modifies the rate of abomasal emptying.3. Hypotonic and isotonic solutions of sodium chloride and sodium bicarbonate increase abomasal emptying but bicarbonate is most effective.4. Increasing the concentration of solutes in the abomasal contents slows abomasal emptying. Sodium chloride, sodium bicarbonate, ammonium chloride and urea do not delay abomasal emptying until hypertonic concentrations are attained. Hypotonic solutions of potassium chloride, calcium chloride, glucose, lactose, hydrochloric acid and acetic acid delay abomasal emptying.5. The results obtained in the calf show that the abomasum is under restraint probably from duodenal receptors as is the simple stomach (Hunt & Knox, 1968) and that an osmoreceptor as postulated by Hunt (1956) is an important factor in this mechanism.6. Acid secretion is inhibited when hypertonic solutions are instilled into the abomasum.7. Pepsin secretion is not affected by simple solutions in the abomasum.8. Gastric function in the milk-fed calf appears to be controlled by mechanisms essentially similar to those already demonstrated in the simple stomach.
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PMID:The effect of some molecules and ions on gastric function in the milk-fed calf. 456 11

A collagenous glycoprotein (Mr 140000) was isolated from dissociative extracts of foetal bovine nuchal ligament and purified by a combination of ion-exchange and gel-filtration chromatography. This glycoprotein (designated MFPI) exists as a large-Mr disulphide-bonded aggregate in the absence of a reducing agent. The purified glycoprotein was shown to contain about 6% (w/w) carbohydrate, mostly as galactose, glucose and mannose. Amino acid analysis showed the presence of hydroxyproline and hydroxylysine, indicative of its collagenous nature. The collagenous nature of this glycoprotein was further investigated by enzyme digestion. Pepsin digestion produced three major fragments, which were identical with peptides of type VI collagen. Bacterial-collagenase digestion of the unreduced glycoprotein also produced several discrete peptides. However, reduction of the glycoprotein before bacterial-collagenase digestion resulted in the degradation of these discrete peptides. Glycoprotein MFPI extracted in dissociative conditions appears to be a larger-Mr form of type VI collagen, believed to originate from microfibrillar components in the intact tissue.
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PMID:A collagenous glycoprotein found in dissociative extracts of foetal bovine nuchal ligament. Evidence for a relationship with type VI collagen. 633 16

Pepsin extracted collagen and an acid soluble glycoprotein were purified from placentas of normal and diabetic human beings. Diabetic samples exhibit a significant increase in ketoamine-linked glucose whereas both amino acid and carbohydrate composition were unaffected. This excess non enzymatic condensation of glucose on free amino-groups was found to increase platelet aggregating potency of these proteins independently of any modification in fiber morphology.
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PMID:Non enzymatic glycosylation increases platelet aggregating potency of collagen from placenta of diabetic human beings. 640 73

We studied biochemically the changes associated with aging and disease in the collagen of articular cartilages and menisci. Pepsin soluble and insoluble collagen were obtained by the method of Miller (1971) from the articular cartilages of seven healthy young and adult, six healthy aged subjects, and of six osteoarthritic and six rheumatoid arthritic patients. One portion of pathological cartilage was histologically examined to eliminate any possible contamination of the fibrous tissue and subchondral bone, and to classify the pathological findings. By the method of Miller, the pepsin soluble and insoluble collagen were also obtained from four adult and six aged menisci. Amino acid composition and carbohydrate contents were studied in insoluble collagen. The type of soluble collagen were analyzed with SDS disc electrophoresis. The amount of crosslinks in insoluble collagen was analyzed by the method of Masuda (1976) using automatic amino acid analyzer. The results obtained where shown as follow: 1) Solubility of collagen by pepsin decreased with aging on articular cartilages and menisci. In osteoarthritis and rheumatoid arthritis, the solubility of collagen by pepsin was different between the samples, and generally higher than that of collagen from the aged articular cartilages. 2) In respect to aldimine crosslinks of insoluble collagen, the dihydroxylysinonorleucine (DHLNL), hydroxylysinonorleucine (HLNL) and lysinonorleucine (LNL) increased with aging. DHLNL and HLNL were present in the nonreduced collagen in vitro. It was shown that the aldimine crosslinks had been already reduced in vivo. 3) The contents of carbohydrate of insoluble collagen from articular cartilage showed lower values than that of type II collagen as described previously. The hexosamine contents increased and those of uronic acid and hexose decreased with aging. In osteoarthritic and rheumatoid arthritic articular cartilages, the contents of uronic acid were lower than that of healthy aged group. The carbohydrate contents of menisci were similar to that of type I collagen. 4) concerning the type of collagen, healthy articular cartilages consisted of type II collagen. In collagen of aged cartilages and those of fibrillated and osteophytic cartilages in osteoarthritic and rheumatoid arthritic patients, the type II collagen were mixed with type I collagen ranging from 13.8% to 64.5%, although the analysis of articular cartilages in this study showed histological characteristics of hyaline cartilage. The type of soluble collagen in adult and aged menisci were composed of type I collagen in spite of aging.
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PMID:[Biochemical study of human articular cartilage and meniscus on aging and joint disease (author's transl)]. 689 84

Crude extracts of starchy endosperm from barley (Hordeum vulgare cv Bomi) contained high pyrophosphorolytic activity (up to 0.5 mumol of glucose-1-P formed min-1 mg-1 of protein) of ADP-glucose pyrophosphorylase (AGP) when assayed in the absence of 3-phosphoglycerate (3-PGA). This high activity was observed regardless of whether AGP had been extracted in the presence or absence of various protease inhibitors or other protectants. Western blot analysis using antibodies specific for either the small or large subunit of the enzyme demonstrated that the large, 60-kD subunit was prone to proteolysis in crude extracts, with a half-time of degradation at 4 degrees C (from 60 to 53 to 51 kD) on the order of minutes. The presence of high concentrations of protease inhibitors decreased, but did not prevent this proteolysis. The small, 51-kD subunit of barley endosperm AGP was relatively resistant to proteolysis, both in the presence or absence of protease inhibitors. For the crude, nonproteolyzed enzyme, 3-PGA acted as a weak activator of the ADP-glucose synthetic reaction (about 25% activation), whereas in the reverse reaction (pyrophosphorolysis) it served as an inhibitor rather than an activator. For both the synthetic and pyrophosphorolytic reactions, inorganic phosphate (Pi) acted as a weak competitive or mixed inhibitor of AGP. The relative insensitivity to 3-PGA/Pi regulation has been observed with both the nonproteolyzed crude enzyme and partially purified (over 60-fold) AGP, the latter characterized by two bands for the large subunit (molecular masses of 53 and 51 kD) and one band for the small subunit (51 kD). Addition of 3-PGA to assays of the partially purified, proteolyzed enzyme had little or no effect on the Km values of all substrates of AGP, but it reduced the Hill coefficient for ATP (from 2.1 to 1.0). These findings are discussed with respect to previous reports on the structure and regulation of higher plant AGP.
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PMID:Insensitivity of barley endosperm ADP-glucose pyrophosphorylase to 3-phosphoglycerate and orthophosphate regulation. 827 93

As part of a structure-function analysis of the higher-plant ADP-glucose pyrophosphorylase (AGP), we used a random mutagenesis approach in combination with a novel bacterial complementation system to isolate over 100 mutants that were defective in glycogen production (T.W. Greene, S.E. Chantler, M.L. Khan, G.F. Barry, J. Preiss, T.W. Okita [1996] Proc Natl Acad Sci USA 93: 1509-1513). One mutant of the large subunit M27 was identified by its capacity to only partially complement a mutation in the structural gene for the bacterial AGP (glg C), as determined by its light-staining phenotype when cells were exposed to l3 vapors. Enzyme-linked immunosorbent assay and enzymatic pyrophosphorylysis assays of M27 cell extracts showed that the level of expression and AGP activity was comparable to those of cells that expressed the wild-type recombinant enzyme. Kinetic analysis indicated that the M27 AGP displays normal Michaelis constant values for the substrates glucose-1-phosphate and ATP but requires 6- to 10-fold greater levels of 3-phosphoglycerate (3-PGA) than the wild-type recombinant enzyme for maximum activation. DNA sequence analysis showed that M27 contains a single point mutation that resulted in the replacement of aspartic acid 413 to alanine. Substitution of a lysine residue at this site almost completely abolished activation by 3-PGA. Aspartic acid 413 is adjacent to a lysine residue that was previously identified by chemical modification studies to be important in the binding of 3-PGA (K. Ball, J. Preiss [1994] J Biol Chem 269: 24706-24711). The kinetic properties of M27 corroborate the importance of this region in the allosteric regulation of a higher-plant AGP.
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PMID:Aspartic acid 413 is important for the normal allosteric functioning of ADP-glucose pyrophosphorylase. 893 21

It is known that some metabolic disturbances may modify the progression of renal disease including primary glomerulonephritis, but the role of purines in this process is still unknown. To investigate this, 13 untreated patients with primary glomerulonephritis were followed up for a mean of 17.6 months to analyze the changes in proteinuria and glomerular filtration rate. On entering the study, each patient was given an oral glucose tolerance test and an oral fructose load test. The areas under the glucose (PGA), insulin (PIA) and uric acid (PUAA, post-fructose) curves were calculated. Glomerulonephritic patients were found to have a statistically higher response to fructose than controls (782 +/- 219 vs 518 +/- 154, P < 0.005). Multiple regression analysis showed that PGA, PIA and PUAA were independently related to changes in proteinuria and glomerular filtration rate during the natural course of the disease. This preliminary study suggests that purine metabolism may modulate the progression of renal disease in proteinuric patients.
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PMID:The relationship between insulin, glucose and serum uric acid and their contribution to the progression of renal damage in patients with primary glomerulonephritis. 895 28

For the development of an efficient gene expression system in a shoyu koji mold Aspergillus oryzae KBN616, the TEF1 gene, encoding translation-elongation factor 1 alpha, was cloned from the same strain and used for expression of polygalacturonase genes. The TEF1 gene comprised 1647 bp with three introns. The TEF1-alpha protein consisted of 460 amino acids possessing high identify to other fungal TEF proteins. Two nucleotide sequences homologous to the upstream activation sequence, characterized for the ribosomal protein genes in Saccharomyces cerevisiae, as well as the pyrimidine-rich sequences were present in the TEF1 gene promoter region, suggesting that the A, oryzae TEF1 gene has a strong promoter activity. Two expression vectors, pTFGA300 and pTFGB200 for production of polygalacturonases A and B respectively, were constructed by using the TEF1 gene promoter. A polygalacturonase (PGB) gene cloned from the same strain comprised 1226 bp with two introns and encoded a protein of 367 amino acids with high similarity to other fungal polygalacturonases. PGA and PGB were secreted at approximately 100 mg/l in glucose medium and purified to homogeneity. PGA had a molecular mass of 41 kDa, a pH optimum of 5.0 and temperature optimum of 45 degrees C. PGB had a molecular mass of 39 kDa, a pH optimum of 5.0 and temperature optimum of 55 degrees C.
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PMID:Utilization of the TEF1-alpha gene (TEF1) promoter for expression of polygalacturonase genes, pgaA and pgaB, in Aspergillus oryzae. 972 Feb 4


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