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)

1. The high oxygen affinity of fetal blood in rabbits is due to a very low concentration of 2,3-diphosphoglycerate (2,3-DPG) in the red cells. In order to gather informations on the factors responsible for this characteristic we have studied synthesis and break-down of 2,3-DPG in fetal and adult rabbit red cells in vitro and examined possible regulative pathways which may lead to the low 2,3-DPG concentration in vivo. 2. Under conditions where 2,3-DPG and 3-phosphoglycerate (3-PGA) accumulate in adult erythrocytes, i.e. in a solution containing inosine, pyruvate and inorganic phosphate, the amount of 2,3-DPG synthetized in fetal red cells was only 40% of the adult value and 3-PGA was not measurable. Upon inhibition of enolase by NaF, however, both 2,3-DPG and 3-PGA increased to a similar extent in fetal and adult red cells. These findings point towards differences in the pyruvate kinase (PK) reaction which is one of the rate limiting steps of glycolysis. Direct measurements revealed an over tenfold higher PK activity in fetal compared to adult red cells. This higher activity of PK will lead to a decreased concentration of 3-PGA with a consecutive fall in 2,3-DPG concentration. 3. Other factors, like a decreased glucose utilization, a decreased activity of 2,3-DPG mutase or an increased 2,3-DPG phosphatase activity could be excluded as a cause for the low 2,3-DPG concentration in fetal red blood cells. The same holds for extraerythrocytic factors like glucose concentration or pH value in fetal blood. 4. During the postnatal development of rabbits the PK activity decreased. 50 days after birth, PK activity was 20% of the fetal value but still somewhat higher than in adult erythrocytes. This change is paralleled by an increase in 2,3-DPG concentration and half saturation oxygen pressure. With respect to the synthesis of 2,3-DPG and ATP, the fetal rabbit red cell is comparable to hereditary high PK activity in human erythrocytes.
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PMID:High pyruvate kinase activity causes low concentration of 2,3-diphosphoglycerate in fetal rabbit red cells. 2 78

To exploit the well documented effect of 2,3-diphosphoglyceric acid (2,3-DPG) in enhancing oxygen delivery by human erythrocytes, we have investigated whether the DPG synthase/phosphatase enzyme system can be targeted to increase DPG levels in the cell. The hydrolytic activity (phosphatase) of the DPG metabolizing enzyme complex exhibits a marked dependence on a physiological effector, 2-phosphoglycolate. Little phosphatase activity is detected in the absence of this activator irrespective of the concentrations of the substrate. The phosphoglycolate-dependent phosphatase activity is competitively inhibited by a glycolytic intermediate, 3-phosphoglyceric acid (3-PGA). The 3-PGA inhibition persists when the 2,3-DPG concentration is raised to saturation level. In contrast, 3-PGA enhances the DPG synthase activity in a dose-dependent manner. In intact red cells, one-half of the cellular DPG content is depleted after 6 hr at 37 degrees C in glucose-free medium. The rate of 2,3-DPG degradation is accelerated when the cellular level of phosphoglycolate is increased by incubation with exogenous glycolate. Together, these results indicate that 2,3-DPG content in erythrocytes can be directly regulated through modulation of phosphatase/synthase activities. In support of this notion, a pyruvate kinase inhibitor, L-alanine, increases by 2-fold the cellular 3-PGA level. This is accompanied by a significant increase (30%) in 2,3-DPG content in human red blood cells. It is postulated that the DPG-promoting action of 3-PGA is mediated through simultaneous phosphatase inhibition and synthase activation. Furthermore, as a result of increased DPG accumulation, the oxygen-hemoglobin dissociation curve in L-alanine-treated cells is rightward shifted by 2.5 torr.
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PMID:2,3-Diphosphoglycerate phosphatase/synthase: a potential target for elevating the diphosphoglycerate level in human red blood cells. 215

We have studied the effects of 2,3-diphosphoglycerate (2,3-DPG), 3-phosphoglycerate (3-PG), 3-phosphoglyceraldehyde (3-PGA), 2-phosphoglycerate (2-PG) and beta-glycerol phosphate (beta-GP) on platelet aggregation and on thromboxane B2 (TXB2) formation. The results show that 2,3-DPG, 3-PG, and 3-PGA inhibited platelet aggregation and TXB2 formation induced by norepinephrine, ADP, epinephrine, and collagen; but they also induced platelet aggregation and TXB2 formation in the presence of subthreshold concentrations of Na arachidonate. 2-PG and beta-GP were inactive. The results also show that there is a structure-function relationship between 2,3-DPG, 3-PG, and 3-PGA with platelet aggregation phenomena and prostaglandin synthesis.
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PMID:Structure-function relationship of 3-phosphoglycerate analogues with platelet aggregation and thromboxane A2 formation. 359 60