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)

The renal prostaglandins PGS2 and PGE2 possess potent antihypertensive and vasodepressor activity. The mechanism of blood pressure lowering effect is through peripheral arteriolar dilation with a fall in total peripheral resistance. PGA unlike PGE escape degradation by the lung and thus could circulate as antihypertensive hormones. Since plasma PGA levels rise in humans on a low sodium intake, it has been postulated that the beneficial effects of a low sodium diet in some hypertensives may be the result of an increase in peripheral vasodilating PGA. Support that plasma PGA may be a regulator of systemic blood pressure is also derived from the fact a PGA-secreting renal tumor was associated with a fall in blood pressure and a rise in plasma PGA in a previously hypertensive woman. The removal of the tumor resulted in a return of blood pressure to elevated levels and a concomitant fall in PGA. Recently, a number of human patients with essential hypertension have been infused with PGA1 and PGA2. It was observed that there was an initial increase in renal blood flow, sodium and water excretion which was associated with no change in the elevated blood pressure. When blood pressure ultimately fell, there was a return of renal blood flow, sodium and water excretion to preinfusion levels. It would appear that PGA compounds act as 'ideal' antihypertensive agents since they favorably effect renal resistance, sodium and water homeostasis, plasma volume, total peripheral resistance, blood pressure and indirectly cardiac output through baroreceptor stimulation, all factors known to be important in etiology in human hypertension.
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PMID:Renal prostaglandins. 110 Oct 92

Total human pepsinogen (PG) was isolated from gastric fundic mucosa and PGA (formerly called PGI) from urine, using standard ion-exchange and gel filtration techniques. Gastric PGA was separated from PGC (formerly called PGII) either by immunoaffinity or high resolution ion-exchange chromatography (fast protein liquid chromatography, Pharmacia, Uppsala, Sweden). The individual PGA isozymogens 2, 3, 4 and 5 could be isolated to homogeneity with the aid of the same ion-exchanger. Evidence was obtained for the existence of secondary modifications of the PGA fractions 3, 4 and 5, electrophoretically overlapping the primary (genetic) isozymogens.
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PMID:Purification of the pepsinogen A isozymogens by means of high resolution ion-exchange chromatography. Evidence for post-translational modifications. 407 Sep 62

Human gastric mucosa contains aspartic proteinases that can be separated electrophoretically on the basis of their physical properties into two major groups: Pepsinogen I (PGA, PGI); and Pepsinogen II (PGC, PGII). Pepsinogens consist of a single polypeptide chain with molecular weight of approximately 42,000 Da. Pepsinogens are mainly synthesized and secreted by the gastric chief cells of the human stomach before being converted into the proteolytic enzyme pepsin, which is crucial for the digestive processes in the stomach. Pepsinogen synthesis and secretion are regulated by positive and negative feed-back mechanisms. In the resting state pepsinogens are stored in granules, which inhibit further synthesis. After appropriate physiological or external chemical stimuli, pepsinogens are secreted in the stomach lumen where hydrochloric acid, secreted by the parietal cells, converts them into the corresponding active enzyme pepsins. The stimulus-secreting coupling mechanisms of pepsinogens appear to include at least two major pathways: one involving cAMP as a mediator, the other involving modification of intracellular Ca(2+)concentration. Physiological or external chemical stimuli acting through the intracellular metabolic adenyl cyclase are more effective in inducing ' de novo ' pepsinogen synthesis than those acting through intracellular Ca(2+). The activation of protein kinase C (PK-C) would appear to be involved in regulatory processes. The measurement of pepsinogens A and C in the serum is considered to be one of the non-invasive biochemical markers for monitoring peptic secretion and obtaining information on the gastric mucosa status of healthy subjects. Recently, pepsinogen measurements have been used as an effective biochemical method for evaluating and monitoring patients with gastrointestinal diseases and for checking the effects of drug treatment. The level of PGA in the serum is always high in normal gastritis, while in atrophic gastritis it is always low. In both cases the PGC level in the serum is high. In most gastrointestinal pathologies the ratio between the PGA/PGC decreases. Various reports concerning hormone and/or enzyme modification as well as gastrointestinal distress in the case of long distance exercise have been reported. It has been suggested that the origin of the gastrointestinal distress experienced by long distance runners is a transient ischaemia of the gastric mucosa; it is also suggested that a hypobaric-hypoxic environment could contribute to induce gastric mucosa necrosis. Interrelation between gastrointestinal distress, hypobaric-hypoxic environment and modifications of PGA and PGC, gastrin and cortisol was evaluated in 13 athletes after a marathon performed at 4300 m. Gastrointestinal symptoms occurred in approximately 40% of the athletes. After the race the athletes showed a significant increase of gastrin and cortisol, while the ratio between PGA/PGC decreased. No relationship was observed between gastrointestinal symptoms and hormonal changes after the race. A control group of five subjects, who had been exposed to the same environmental conditions, showed no gastrointestinal or hormonal alteration. Conversely, control subjects presented a significant decrease of cortisol related to the circadian rhythm. The same incidence of gastrointestinal symptoms at high altitude and at sea level and the absence of pathological alteration of PGA and PGC in the serum of the athletes indicates that running a marathon and living for 6 days at 4300 m does not induce gastric mucosa necrosis. Cortisol and gastrin alteration observed in the athletes at this altitude would seem to be related to an activation of the mesopontine and forebrain structures involved in the behavioural and metabolic integration of the autonomic control and arousal and psychophysical-exercise stress. 2000 Academic Press@p$hr
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PMID:Pepsinogens: physiology, pharmacology pathophysiology and exercise. 1067 78

The interaction between fungal endopolygalacturonases (EPGs) and polygalacturonase-inhibiting proteins (PGIPs) found in plant cell walls has been well established. The typical EPG/PGIP interaction is characterized by high affinity, reversibility, and a 1:1 stoichiometry that results in lowering the catalytic rate of a particular endopolygalacturonase by up to 99.7%. Various EPG and PGIP isoforms and glycoforms have been isolated and characterized, and combinations of EPGs and PGIPs demonstrate a range of enzyme inhibition. EPG/PGIP interactions have prompted many researchers to suspect the involvement of these proteins in the production of specific signals (oligosaccharins) during plant pathogenesis. We have recently reported on initial studies in our laboratory indicating that, for certain EPG/PGIP combinations, the specific activity of EPG is increased beyond that characteristic of the enzyme alone. In this paper, we present a detailed analysis of the product of the interaction of native Phaseolus vulgaris PGIP-2 with five EPGs from Aspergillus niger, namely PGI, PGII, PGA, PGB, and PGC in the presence of homogalacturonan. We demonstrate that for PGA and PGC, the interaction with PGIP-2 may result in either inhibition or activation in a manner that is pH dependent. This data suggests the need for a reevaluation of the conventional description applied to PGIPs; suggestions include polygalacturonase-binding protein and polygalacturonase-modulating protein.
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PMID:Polygalacturonase-inhibiting proteins can function as activators of polygalacturonase. 1530 10

Morphology and compliance of tissue-engineered blood vessels (TEBV) are dependent on the culture period and production of extracellular matrix (ECM) components in order to increase the strength of the developing tissue. The aim of the present study was to evaluate the potential of TEBVs to produce an ECM similar to native arteries and veins. Human smooth muscle cells (SMC) were seeded onto the poly(glycolic acid) (PGA) scaffold and placed in bioreactors filled with DMEM supplemented with growth factors. After 6 weeks, the vessels were harvested from the bioreactors and seeded with human endothelial cells at the lumen for another 3 days. Then, the TEBVs were harvested for RNA and protein isolation for further RT-PCR and Western blot. TEBVs had a similar macroscopic appearance to that of native vessels with no visible evidence of the original PGA. Histological and immunohistochemical analyses indicated the presence of high cell density and development of a highly organized structure of ECM. After 6 weeks of culture, there were significantly lower gene expression of SMC-specific markers, such as alpha-actin, caldesmon, and vimentin, and proteoglycans, such as biglycan, decorin, and versican, and other ECM components, such as collagen I and elastin, in TEBVs, with and without pulsatile conditions, compared to that of native arteries. Gene expression of fibronectin was significantly lower in TEBVs grown during pulsatile conditions compared to that of native arteries. No difference was observed in TEBVs grown during non-pulsatile conditions. The presence of alpha-actin, collagen I, decorin, and fibronectin at protein level was demonstrated in TEBVs with and without pulsatile conditions after 6 weeks and in native veins and arteries as well. How this deviation translates into mechanical properties remains to be explored.
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PMID:Production of extracellular matrix components in tissue-engineered blood vessels. 1667 96