DAO Activity Research Articles

Distribution of polyamines and their related catabolic enzyme in etiolated and light-grown leguminosae seedlings

Diamine-oxidase (DAO; EC 1.4.3.6) activity and di-and polyamine levels were estimated along the epicotyl and root of light-grown and etiolated lentil (Lens culinaris Medicus) and pea (Pisum sativum L.) seedlings. The activity of DAO was higher in etiolated epicotyls than in lightgrown ones. In both species there was a positive correlation between DAO activity and the diamine (putrescine and cadaverine) levels along the whole epicotyl and root. Polyamine (spermine and spermidine) distribution seemed to be associated with the meristematic and elongating zone of the epicotyl and root. The physiological function of DAO is discussed in relation to its possible role in providing hydrogen peroxide to peroxidase-dependent reactions occurring in the cell wall.

Enzymatic histamine catabolism in vertebrate ontogenesis. A comparative study

1. The synthesizing and degrading activities of histamine were determined in the liver and small intestine of developing guinea pig and chick embryos. 2. Though increasing with age, HDC values were always 2–3 orders of magnitude lower than those of degrading enzymes. 3. DAO activity on the other hand was 10–100 fold higher than HMT at all ages studied, suggesting a decisive role for oxidative deamination in control of tissue histamine levels. 4. Generally histamine levels were higher in tissues of developing guinea pig than chick embryo, however, in the laying hen intestine histamine concentration was approximately 5 times greater than in the adult guinea pig intestine.

Role of polyamines in intestinal adaptation in the rat.

The cellular mechanisms controlling adaptive intestinal mucosal hypo- and hyperplasia are poorly understood but changes in tissue polyamine levels and in the activity of the key enzymes controlling their synthesis (ornithine decarboxylase: ODC) and degradation (diamine oxidase: DAO) have been implicated. Therefore, in two models of adaptive mucosal hyperplasia (pancreatico-biliary diversion, PBD, achieved by surgically transposing the jejunum to lie between pylorus and ampulla of Vater, and 90% small bowel resection, SBR-both studied 8 weeks after surgery) and in one model of hypoplasia (8 days total parenteral nutrition) we measured indices of mucosal mass (wet weight, protein and DNA per 10-cm intestine), the growth-associated polyamines (putrescine, spermidine and spermine per 10-cm intestine and per mg DNA) and DAO activity in the duodenum, five 10-cm segments of jejunum, five 10-cm segments of ileum and in the colon, and compared the results with those found in transected or unoperated controls. The results for the indices of mucosal mass confirmed that TPN led to a modest degree of small bowel mucosal hypoplasia whilst PBD, and particularly 90% SBR, stimulated marked adaptive hyperplasia. There were corresponding changes in the amounts of putrescine and spermidine (but not of spermine)-not only when the results were expressed per unit length but also when calculated per mg mucosal DNA and in the ratio of spermidine:spermine. There was an increasing proximal-to-distal gradient in mucosal DAO per unit length intestine in all experimental groups but when the results were expressed per mg DNA, the ileal DAO levels were significantly reduced in the PBD and resection groups, when compared with the controls. These data support the hypothesis that polyamines play a major, and perhaps a controlling, role in regulating adaptive intestinal mucosal growth.

Ornithine decarboxylase, transglutaminase, diamine oxidase and total diamines and polyamines in maternal liver and kidney throughout rat pregnancy.

Ornithine decarboxylase (ODC; EC 4.1.1.17), transglutaminase (EC 2.3.2.13), diamine oxidase (DAO; EC 1.4.3.6) and total di- and poly-amines were studied in rat liver and kidney cortex throughout pregnancy. In liver, ODC activity exhibited two major peaks (4.5-5 times the control activities) on days 15 and 17. Also putrescine and spermidine increased biphasically (3-4-fold), but no variation in spermine content was observed. Transglutaminase activity showed slight variations only near the end of gestation. In kidney, ODC activity did not fluctuate significantly during pregnancy, whereas both transglutaminase activity and putrescine content showed three major increases, in very early, middle and late pregnancy. No significant variations in spermidine and spermine were observed. In both organs, DAO activity, very low or undetectable until day 10, dramatically increased (10- and 20-fold in kidney and liver respectively) in the second half of pregnancy, reaching maxima on days 16-17 and 19. The results obtained for transglutaminase, ODC and total di- and poly-amines are interpreted on the basis of hyperplastic and hypertrophic events in the liver and kidney respectively. The behaviour of DAO suggests that the enzyme plays an important role in the control of intracellular diamine concentration.

Radiation Effects on Diamine Oxidase Activities in Intestine and Plasma of the Rat

Diamine oxidase (DAO; EC 1.4.3.6) activity was measured in plasma and in ileal tissue homogenates prepared from male Sprague-Dawley rats euthanized at 1-15 days after acute whole-body irradiation with 14.5-MeV electrons. Animals irradiated with 1 Gy showed no diminution in plasma and ileal DAO activities through Day 13 relative to nonirradiated controls. Animals irradiated with 5, 10, and 12 Gy displayed marked declines in ileal DAO activity, with levels reaching a nadir on Day 3. This was paralleled by a decrease in plasma DAO activity in all three dose groups. Recovery of ileal and plasma DAO levels was later seen as early as Day 4 in animals irradiated with 5- and 10-Gy doses, but animals receiving 12 Gy did not survive beyond Day 3. The relationship between radiation dose and levels of plasma and ileal DAO on Day 3, the time of maximum decrease at all doses, was also investigated. Ileal DAO activity decreased almost linearly between 2 and 8 Gy. Plasma DAO activity closely paralleled the dose dependency of the ileal levels. These data suggest that plasma DAO activity might be useful as a biologic marker of intestinal epithelial injury and recovery after acute radiation exposure.

A sum of 14C-putrescine metabolites as a measure of DAO activity. Column chromatography assay.

The rapid ion-exchange chromatographic method was developed for the separation of 14C-putrescine from its metabolites arising from diamine oxidase (DAO, E.C. 1.4.3.6) catalysed reaction. The assay is linear for putrescine conversion with both, time and enzyme concentration. With this method many samples could be analysed simultaneously.

Plasma postheparin diamine oxidase. Sensitive provocative test for quantitating length of acute intestinal mucosal injury in the rat.

Diamine oxidase (DAO; EC 1.4.3.6) is an enzyme found in high activity in the mature cells of the upper villus of rat small intestinal mucosa and in very much lower activity in all other tissues in the nonpregnant rat. This study was designed to determine whether a provocative test for increasing the level of plasma DAO activity by heparin administration could be used to monitor the extent and severity of acute, severe, small intestinal mucosal injury. In adult rats, small intestinal loops of varying lengths were perfused with 2,100 mosM sodium sulfate solution for 60 min to produce selective damage to villus epithelium. Plasma postheparin DAO (PHD) activity (180 min after 400 U/kg i.p. heparin) was measured 7 h after initiation of perfusion. With increasing length of intestinal mucosal injury, there was a progressive decrease in both basal and plasma PHD activity. The decrease in plasma PHD activity closely reflected the length of intestinal mucosa injured (n = 128, r = 0.86, P less than 0.001), and it was much more sensitive (threshold limit of detection = 13% of total length, range = 67 U/ml for 100% length of injury) than unstimulated basal levels of plasma DAO (threshold = 40%, range = 2.1 U/ml). Our previous data have suggested that DAO is unique among intestinal mucosal enzymes in that circulating levels can serve as a marker of mucosal injury; this study illustrates that the addition of a low-dose heparin administration enhances the use of DAO even further as a sensitive, quantitative, circulating marker for monitoring the extent of small intestinal mucosal injury in the rat.

Diamine oxidase activity and imidazoleacetic acid formation in the foetal and maternal guinea pig liver

Diamine oxidase activity and imidazoleacetic acid formation in the foetal and maternal guinea pig liver during gestation were examined. DAO activity and IMAA formation in the foetal liver increased continuously, while maternal enzyme activity and ImAA formation in the second half of pregnancy simultaneously decreased. The roles of GABA and ImAA are discussed.

Plasma amine oxidases in Wilson's disease

Plasma Mono- and Diamine-Oxidase activities (MAO and DAO), two copper containing enzymes, were estimated in 5 patients with Wilson's disease, without treatment and during D-Penicillamine treatment. Ceruloplasmin and “free” copper plasma levels were simultaneously measured. MAO was elevated in all cases, while DAO was within normal limits. D-Penicillamine administration did not result in significant reductions of these enzyme activities. It is likely that alterations of copper metabolism induced by Wilson's disease and by D-Penicillamine administration do not affect the activity of MAO or DAO. The increase in MAO activity in Wilson's disease probably results from the hepatic fibrosis.

Putrescine metabolism and the study of diamine oxidase activity in vivo.

The catabolism of 14C-putrescine (1,4-tetramethylene-diamine) to labeled CO2 in small laboratory animals has been studied extensively in order to establish the influence of nutritional, endocrine and other factors on this process. Special attention has been paid to treatments that are known to affect the activity of diamine oxidase (DAO, histaminase, EC, 1.4.3.6), a copper-containing enzyme characteristically inhibited by semicarbazide. Thus, copper-deficient rats metabolize putrescine more slowly than their controls. Antimalarial drugs that inhibit histamine N-methyltransferase also inhibit putrescine catabolism in vivo and DAO activity in vitro. Adrenalectomized rats metabolize the diamine at a reduced rate, a result consistent with the previously demonstrated decrease of DAO in the tissues of several species of animal. There is no effect on the rate of catabolism of putrescine when thyroid state is altered. Heparin (up to 15,000 U/kg), which releases DAO from the small (0.1 mg/kg), intestine, and aminoguanidine (0.1 mg/kg), which inhibits the enzyme powerfully, both cause decreased rates of catabolism of the diamine in rats. The putrescine-catabolizing ability returns with a half-time of recovery of 15-18 h, corresponding to the estimates of SHAFF and BEAVEN [36] for recovery of intestinal DAO activity following administration of heparin or cycloheximide. Together with out other results this suggests that what is being measured by putrescine catabolism depends to a significant extent on the activity of DAO in vitro.

Effect of intrapulmonary heparin on plasma diamine oxidase (histaminase) activity in mice.

Heparin releases diamine oxidase (DAO, histaminase) from binding sites in the intestinal vasculature. Histamine is involved in a number of pathological lesions. In this study we have examined the effect of intrapulmonary administration of heparin on plasma DAO activity in mice. For comparative purposes the same parameter was measured following the administration of an intravenous heparin regimen. The time course and dose-response were examined with the two heparin regimens. The doses of heparin were based on appropriate clinical equivalents. Both heparin regimens showed a dose dependent response (correlation coefficient r = 0.9). The dose of intrapulmonary heparin (10 mg/kg) was 12 times greater than the dose injected intravenously but the DAO response lasted 48 times longer that that obtained from the intravenous heparin regimen.

Determination of diamine oxidase (histaminase) activity. An interference of aldehyde metabolizing enzymes [proceedings

The results obtained with various inhibitors suggest that for exact estimation of DAO activity in many tissue homogenates it is not sufficient to estimate simply the amount ofΔ1-pyrroline formed during reaction.

Role of Histidine and Tyrosine Decarboxylases and Mono- and Diamine Oxidases in Amine Build-Up in Cheese

Presence of biologically active amines in foods has been recognized for about 20 years. Past research on amines such as tyramine and histamine has not investigated factors which account for the variable concentrations often found in food products. This research was designed to investigate the roles of tyrosine and histidine decarboxylase activities and mono- and diamine oxidases (MAO and DAO) in amine formation and catabolism in cheese. The data indicate that the presence of decarboxylases is probably not the limiting factor for amine build-up. Most cheeses contained decarboxylase activities for both tyrosine and histidine; however, tyramine and histamine were present in some cheeses which did not contain detectable levels of the corresponding decarboxylases at the time of sampling. Few cheeses possessed MAO or DAO activities. When the oxidases were present, the amine contents were usually lower. A Colby cheese containing tyramine and histamine with high MAO activity also possessed high tyrosine decarboxylase activity. It appears that a major limiting factor in formation of biologically active amines in cheese is the availability of free amino acids for decarboxylation. Dairy-related bacteria generally lacked the amine oxidases. However, five of six dairy-related cultures with highly active decarboxylases showed MAO or DAO activities. The culture showing the highest DAO activity, Microbacterium lacticum, possessed low tyrosine and histidine decarboxylase activities.

Colorimetric estimation of diamine oxidase activity

A simple colorimetric method for estimation of DAO activity with 4-nitrobenzylamine as a substrate (9,10) was developed. Sensitivity of this method, based on conversion of the aldehyde formed in course of the enzymatic reaction into its 4-nitrophenylhydrazone with subsequent measuring of optical density at 590 nm in strongly alkaline medium, exceeded about 25-fold that of the conventional colorimetric procedure for estimation of DAO activity (14). Sensitivity of the spectrophotometric method for estimation of DAO activity with 4-dimethylaminomethylbenzylamine as a substrate (4) was increased about fivefold by conversion of the aldehyde formed in course of the enzymatic reaction into its 4-nitrophenylhydrazone with subsequent measuring of optical density at 530 nm in strongly alkaline medium.

Association of diamine oxidase with microsomal membranes in rabbit liver

Diamine oxidase (diamine O 2 oxidoreductase, EC 1.4.3.6, DAO) of rabbit liver is localized in the microsomal fraction (1, 2). Microsomes, freed of adsorbed and intraluminal proteins by washing procedures, still retain all DAO activity. This indicates that DAO belongs to the microsomal membrane itself. While the release of DAO activity from washed microsomes occurs exclusively in the presence of high concentrations of deoxycholate, tight binding of this enzyme to the membrane structure is apparent.

The clinical-chemical application of the NADH test for the determination of diamine oxidase activity in human pregnancy.

The combined optical test for measuring DAO activity in serum of pregnant women was proved to possess a satisfactory reliability. On the average, gestational diseases related to placental insufficiency showed significantly elevated DAO activities in the 29th to 34th week of pregnancy, but lowered activities in the 35th to 40th week of pregnancy. In single cases also normal values of DAO activity were found in complicated gravidity. But when the DAO activities were higher than 0.7 mU/ml or lower than 0.15 mU/ml, never a normal pregnancy was found.

Enzymic properties of diamine oxidase from hog kidney.

DAO was partially purified from hog kidney by a procedure involving differential centrifugation, heat treatment and ammonium sulfate fractionation. The enzymic properties of partially purified DAO were studied with cadaverine and histamine as substrates and the following results were obtained. The specific activities of hog kidney DAO at the final step of purification were 183-fold and 125-fold those of the crude homogenate with histamine and cadaverine, respectively, as substrates. With cadaverine and histamine the pS maxima values were 3×10-3 M and 1×10-3 M and the pH optima were 7.1 and 6.5, respectively. All the diamines tested, (i.e. cadaverine, putrescine, hexamethylenediamine, histamine, ethylenediamine and agmatine) were oxidized with this enzyme, while monoamine, (i.e. tyramine, benzylamine, serotonin, β-phenylethylamine, n-amylamine and n-propylamine) were not. DAO activity was inhibited by aminoguanidine, hydroxylamine, MPH and semicarbazide. The inhibitory effects were similar when either cadaverine or histamine was used as substrate. SH-reagents, such as PCMB and iodoacetoamide, did not affect DAO activity, but various metal ions, such as CuCl, Cu(NO3)2, Zn(NO3)2, AlCl3 and Fe(NO3)3 were inhibitory. The inhibitory effect of AgNO3 on DAO activity differed greatly, when using cadaverine and histamine as substrates. The temperature-in-activation curves of DAO measured with cadaverine and with histamine were different.

Enzymic properties of diamine oxidase from hog kidney

DAO was partially purified from hog kidney by a procedure involving differential centrifugation, heat treatment and ammonium sulfate fractionation. The enzymic properties of partially purified DAO were studied with cadaverine and histamine as substrates and the following results were obtained. The specific activities of hog kidney DAO at the final step of purification were 183-fold and 125-fold those of the crude homogenate with histamine and cadaverine, respectively, as substrates. With cadaverine and histamine the pS maxima values were 3 × 10-3 M and 1 × 10-3 M and the pH optima were 7.1 and 6.5, respectively. All the diamines tested, (i.e. cadaverine, putrescine, hexamethylenediamine, histamine, ethylenediamine and agmatine) were oxidized with this enzyme, while monoamine, (i.e. tyramine, benzylamine, serotonin, ß-phenylethylamine, n-amylamine and n-propylamine) were not. DAO activity was inhibited by aminoguanidine, hydroxylamine, MPH and semicarbazide. The inhibitory effects were similar when either cadaverine or histamine was used as substrate. SH-reagents, such as PCMB and iodoacetoamide, did not affect DAO activity, but various metal ions, such as CuCl, Cu(N03)2, Zn(N03)2, A1C13 and Fe-(N03)3 were inhibitory. The inhibitory effect of AgN03 on DAO activity differed greatly, when using cadaverine and histamine as substrates. The temperature-inactivation curves of DAO measured with cadaverine and with histamine were different.

Diamine oxidase isoenzymes in human blood plasma.

The pregnancy-induced activity of diamine oxidase (DAOpr) disappears from blood plasma after parturition with a ‘half-life’ (T1/2) of 30 hours, whereas transfused DApr is eliminated with T1/2 about 20 hours. In contrast, the in creased plasma activity of DAO in heparinized subjects (DAOhep) has a T1/2 of about 1 hour in the eliminatory phase, and, when transfused, DAOhep is with drawn from circulation with a T1/2 of about 3 min. In vitro studies of DAOpr and DAOhep have shown very similar enzyme characteristics of DAOpr and DAOhep, whereas they differed in electrophoretic mobility. DAOhep and DAOpr may thus be regarded as diamine oxidase isoenzymes.

Inhibition of amine oxidases by nitrofuran derivatives: possible structure-activity relations and criteria of irreversibility.

Four bacteriostatically active nitrofurfurylidene compounds and their respective hydrazine moieties were administered to male Wistar rats. MAO activity was measured in vivo by different methods in liver, brain, and small intestine. Inhibition of DAO activity was determined in small intestine of rats and, in in-vitro experiments, in a partially purified pig kidney enzyme preparation.