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Diamine Oxidase (diamine + oxidase)
Selected AbstractsEvaluation of intestinal mucosal function by measuring expired 14CO2 after oral administration of 14C-putrescineJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 9 2001Akira Sasaki Abstract Background: Diamine oxidase (DAO) is the enzyme that degrades putrescine, the key main product of polyamine metabolism, and reflects enterocytic maturity of absorption because diamine oxidase activity is highest in the small intestine. We have already shown that expired 14CO2 after oral administration of 14C-putrescine correlated with intestinal DAO activity. However, the influence of food composition and the mucosal adaptation after intestinal resection have not been elucidated. Methods: Male Wistar rats were fed normal chow or an elemental diet (ED) for 2 weeks. Resected rats underwent 50% jejunectomy or 50% ilectomy. Expired 14CO2 levels, following oral administration of 14C-putrescine were measured in all rats, and compared with the intestinal DAO activity and other mucosal parameters. Results: In the ED group, the 14CO2 levels reached a peak earlier, and values were 2.9-fold higher than in the group fed with normal chow. Mucosal alkaline phosphatase (ALP) and DAO activity in the ED group were also higher than in the group fed normal chow, although the mucosal wet weight was significantly lower in the ED group. In the resection groups, all expired 14CO2 values increased during measurement. The peak 14CO2 values in the jejunectomy group shifted earlier in the postoperative period. The mucosal DAO activity in both the resection groups was higher than it was in the control group at the fifth and 10th postoperative day. However, there were no differences among the three groups at the 15th postoperative day. Conclusions: Our studies suggested that expired 14CO2 after oral administration of 14C-putrescine correlates with mucosal DAO activity, and that it also reflects intestinal function. [source] Polyamine metabolism and cancerJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 2 2003Thresia Thomas Abstract Polyamines are aliphatic cations present in all cells. In normal cells, polyamine levels are intricately controlled by biosynthetic and catabolic enzymes. The biosynthetic enzymes are ornithine decarboxylase, S-adenosylmethionine decarboxylase, spermidine synthase, and spermine synthase. The catabolic enzymes include spermidine/spermine acetyltransferase, flavin containing polyamine oxidase, copper containing diamine oxidase, and possibly other amine oxidases. Multiple abnormalities in the control of polyamine metabolism and uptake might be responsible for increased levels of polyamines in cancer cells as compared to that of normal cells. This review is designed to look at the current research in polyamine biosynthesis, catabolism, and transport pathways, enumerate the functions of polyamines, and assess the potential for using polyamine metabolism or function as targets for cancer therapy. [source] Polyamine metabolism in barley reacting hypersensitively to the powdery mildew fungus Blumeria graminis f. sp. hordeiPLANT CELL & ENVIRONMENT, Issue 3 2002T. Cowley Abstract Polyamine levels and activities of enzymes of polyamine biosynthesis and catabolism were examined in the barley cultivar Delibes (Ml1al + Ml(Ab)) reacting hypersensitively to the powdery mildew fungus, Blumeria graminis f. sp. hordei (race CC220). Levels of free putrescine and spermine and of conjugated forms of putrescine, spermidine and spermine were greatly increased 1,4 d following inoculation of barley with the powdery mildew. These changes in polyamine levels were accompanied by elevated activities of the polyamine biosynthetic enzymes ornithine decarboxylase (ODC), arginine decarboxylase (ADC) and S -adenosylmethionine decarboxylase (AdoMetDC) and the polyamine catabolic enzymes diamine oxidase (DAO) and polyamine oxidase (PAO). Activities of two enzymes involved in conjugating polyamines to hydroxycinnamic acids, putrescine hydroxycinnamoyl transferase (PHT) and tyramine feruloyl-CoA transferase (TFT) were also examined and were found to increase significantly 1,4 d after inoculation. The possibility that the increased levels of free spermine, increased polyamine conjugates, and increased DAO and PAO activities are involved in development of the hypersensitive response of Delibes to powdery mildew infection is discussed. [source] ECL Cell Histamine Mobilization Studied byGastric Submucosal Microdialysis in Awake Rats:Methodological ConsiderationsBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 2 2003Peter Ericsson They secrete histamine in response to circulating gastrin. Gastric submucosal microdialysis has been used to study ECL-cell histamine mobilization in awake rats. In the present study we assess the usefulness and limitations of the technique. Microdialysis probes were implanted in the gastric submucosa. Histological analysis of the stomach wall around the probe revealed a moderate, local inflammatory reaction 1,2 days after implantation; the inflammation persisted for at least 10 days. Experiments were conducted 3 days after the implantation. The "true" submucosal histamine concentration was determined by perfusing at different rates (the zero flow method) or with different concentrations of histamine at a constant rate (the no-net-flux method): in fasted rats it was calculated to be 87±5 (means±S.E.M.) nmol/l and 76±9 nmol/l, respectively. The corresponding histamine concentrations in fed rats were 93±5 and 102±8 nmol/l, respectively. With a perfusion rate of 74 ,l/hr the recovery of submucosal histamine was 49%, at 34 ,l/hr the recovery increased to 83%. At a perfusion rate below 20 ,l/hr the microdialysate histamine concentration was close to the actual concentration in the submucosa. The ECL-cell histamine mobilization was independent of the concentrations of Ca2+ in the perfusion medium (0,3.4 mmol/l Ca2+). In one experiment, histamine mobilization in response to gastrin (10 nmol/kg/hr subcutaneously) was monitored in rats pretreated with prednisolone (60 mg/kg) or indomethacin (15 mg/kg). The two antiinflammatory agents failed to affect the concentration of histamine in the microdialysate either before or during the gastrin challenge, which was in accord with the observation that the inflammatory reaction was modest and that inflammatory cells were relatively few around the probe and in the wall of the probe. In another experiment, rats were given aminoguanidine (10 mg/kg) or metoprine (10 mg/kg) 4 hr before the start of gastrin infusion (5 nmol/kg/hr intravenously). Metoprine (inhibitor of histamine N-methyl transferase) did not affect the microdialysate histamine concentration, while aminoguanidine (inhibitor of diamine oxidase) raised both basal and gastrin-stimulated histamine concentrations. We conclude that microdialysis can be used to monitor changes in the concentration of histamine in the submucosa of the stomach, and that the inflammatory reaction to the probe is moderate and does not affect the submucosal histamine mobilization. [source] A new crystal form of human diamine oxidaseACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 2 2010Aaron P. McGrath Copper amine oxidases (CAOs) are ubiquitous in nature and catalyse the oxidative deamination of primary amines to the corresponding aldehydes. Humans have three viable CAO genes (AOC1,3). AOC1 encodes human diamine oxidase (hDAO), which is the frontline enzyme for histamine metabolism. hDAO is unique among CAOs in that it has a distinct substrate preference for diamines. The structure of hDAO in space group P212121 with two molecules in the asymmetric unit has recently been reported. Here, the structure of hDAO refined to 2.1,Å resolution in space group C2221 with one molecule in the asymmetric unit is reported. [source] | ||||||||||