Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.1.4 (deaminase)
 5,113 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. A method is described for detecting and determining the products of metabolism of ADP added to plasma at initial concentrations of about 1mum-ADP. 2. ATP, ADP, AMP, adenosine, inosine and hypoxanthine were detected in human platelet-rich plasma after incubation with ADP and in the presence of either heparin or heparin-citrate. 3. The products of incubation of ADP with human platelet-poor plasma in the presence of heparin were the same as with platelet-rich plasma, except that, when the initial concentration of ADP was 1.5mum, little or no ATP was detected. 4. The ATP detected in platelet-rich plasma when 1.5mum-ADP was initially incubated was present in the platelets and not in the plasma. 5. The time for 50% decay of ADP in either platelet-rich or platelet-poor plasma in the presence of heparin was about 20min. when the initial concentration of ADP was 200mum, but was 6-9min. when the initial ADP concentration was 1.5-2.5mum. The corresponding values in the presence of heparin-citrate were about 45min. and about 9-12min. respectively. 6. Hypoxanthine accumulated to a greater extent in platelet-rich than in platelet-poor plasma after the addition of ADP. 7. After incubation for 15-20min. of either platelet-rich plasma or suspensions of washed platelets in saline with adenosine at an initial concentration of about 3-4mum, ATP, ADP and AMP were detected in the platelets. Similar incubations of washed platelets with inosine also showed the formation of these substances, but to a much less extent. 8. After the addition of adenosine to suspensions of washed platelets in saline, inosine and hypoxanthine were detected in the incubation mixture. After the addition of inosine, hypoxanthine was detected. 9. When ADP at an initial concentration of 1.5mum was added to platelet-rich plasma containing adenosine deaminase, no adenosine was detected in the incubation mixture. There was no difference in the rate of decay of ADP in the presence or absence of the deaminase, but ATP formation was decreased in its presence.
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PMID:Detection and determination of adenosine diphosphate and related substances in plasma. 594 46

Because adenine nucleotide catabolites may be important during postischemic lung reperfusion, we examined the pathway of adenosine monophosphate (AMP) degradation in ischemic lung tissue. Once the pattern of degradation is known, pharmacological interventions can be considered, offering new methods of reducing lung reperfusion injury. For this purpose we used the isolated rabbit lung. Rabbit lungs were flushed in situ with a modified Krebs Henseleit solution (60 ml/kg). The lungs were removed and stored deflated, immersed in saline solution at 37 degrees C. At regular times, biopsies were taken, and adenine nucleotides, nucleosides, and bases were measured in these biopsies using high performance liquid chromatography (HPLC). During lung ischemia, a very significant increase of inosine monophosphate (IMP) was found. Adenosine levels on the other hand did not increase. Hypoxanthine was the major end catabolite of ischemic lung tissue (constituting 92% of the nucleoside and purine base fraction at 4 hours ischemia). To further determine the pathway of AMP degradation, 400 mM of the adenosine deaminase inhibitor erythro-9-[2-hydroxy-3-nonyl]adenine (EHNA) was added to the lung flush solution. During ischemia, adenosine triphosphate (ATP) breakdown was unaltered but adenosine became the major catabolite (2.8 times the concentration of hypoxanthine at 4 hours ischemia). These data suggest that: 1) in rabbit lung tissue, dephosphorylation of AMP to adenosine is more important than deamination to IMP; 2) hypoxanthine is the major end catabolite of ischemic lung tissue. By inhibiting the enzyme deaminase, reduced hypoxanthine levels and increased adenosine levels were obtained. Pharmacological interventions are now available to interfere with the formation of adenine nucleosides and bases in ischemic lung tissue. The importance of adenine nucleotide catabolites to postischemic lung reperfusion injury is discussed.
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PMID:Pattern of AMP degradation in ischemic rabbit lung tissue. 773 34

Hypoxanthine catabolism in vivo is potentially dangerous as it fuels production of urate and, most importantly, hydrogen peroxide. However, it is unclear whether accumulation of intracellular and supernatant hypoxanthine in stored red blood cell units is clinically relevant for transfused recipients. Leukoreduced red blood cells from glucose-6-phosphate dehydrogenase-normal or -deficient human volunteers were stored in AS-3 under normoxic, hyperoxic, or hypoxic conditions (with oxygen saturation ranging from <3% to >95%). Red blood cells from healthy human volunteers were also collected at sea level or after 1-7 days at high altitude (>5000 m). Finally, C57BL/6J mouse red blood cells were incubated in vitro with 13C1-aspartate or 13C5-adenosine under normoxic or hypoxic conditions, with or without deoxycoformycin, a purine deaminase inhibitor. Metabolomics analyses were performed on human and mouse red blood cells stored for up to 42 or 14 days, respectively, and correlated with 24 h post-transfusion red blood cell recovery. Hypoxanthine increased in stored red blood cell units as a function of oxygen levels. Stored red blood cells from human glucose-6-phosphate dehydrogenase-deficient donors had higher levels of deaminated purines. Hypoxia in vitro and in vivo decreased purine oxidation and enhanced purine salvage reactions in human and mouse red blood cells, which was partly explained by decreased adenosine monophosphate deaminase activity. In addition, hypoxanthine levels negatively correlated with post-transfusion red blood cell recovery in mice and - preliminarily albeit significantly - in humans. In conclusion, hypoxanthine is an in vitro metabolic marker of the red blood cell storage lesion that negatively correlates with post-transfusion recovery in vivo Storage-dependent hypoxanthine accumulation is ameliorated by hypoxia-induced decreases in purine deamination reaction rates.
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PMID:Hypoxia modulates the purine salvage pathway and decreases red blood cell and supernatant levels of hypoxanthine during refrigerated storage. 2907 93