Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:1.17.3.2 (xanthine oxidase)
8,383 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The rate constants for the interactions of superoxide with vitamin E (alpha-tocopherol), vitamin C (ascorbic acid) and their related compounds have been measured by a chemiluminescence method. A strong chemiluminescence of a constant intensity was observed when xanthine oxidase was added to an aqueous solution of hypoxanthine and a Cypridina luciferin analog, 2-methyl-6-phenyl-3-7-dihydroimidazo[1,2-a]pyrazin-3-one (CLA). Vitamin E, vitamin C and their related compounds competed with CLA to react with superoxide and reduced the chemiluminescence intensity. From a kinetic analysis of the effect of addition of these compounds on the chemiluminescence intensity, the rate constants for their interactions with superoxide were measured at 25 degrees C and pH 7.8. The rate constants were obtained as 3.3 x 10(5) and 1.7 x 10(4) M-1 s-1 for ascorbate and 2-carboxy-2,5,7,8-tetramethyl-6-chromanol, respectively, and also as 4.9 x 10(3) and 4.5 x 10(3) M-1 s-1 for alpha-tocopherol incorporated into soybean and dimyristoyl phosphatidylcholine liposomal membranes, respectively. It has been shown that this method is a sensitive and a quick method which can be applied for measurement of the reactivities of various natural and synthetic compounds toward superoxide. In addition it has been shown that this method can also be applied to the heterogeneous system as well as homogeneous solution, which makes it more versatile and useful for the study in biochemistry.
...
PMID:Rates of interactions of superoxide with vitamin E, vitamin C and related compounds as measured by chemiluminescence. 131 Aug 74

A highly sensitive chemiluminescence method for determining superoxide dismutase (SOD) activities in human gastric mucosa obtained by endoscopic biopsy is described. As the chemiluminescence probe, we used Cypridina luciferin analogue (CLA), a very sensitive and specific probe to detect superoxide generated from hypoxanthine-xanthine oxidase system. SOD activity in the gastric mucosa was assayed by the inhibition of CLA-dependent chemiluminescence in highly diluted tissue homogenates. SOD activity was distributed throughout the gastric mucosa. The marginal mucosa of peptic ulcers showed significantly lower SOD activity when the ulcer was in the active stage, and during the healing stage showed high activity when compared to the endoscopically normal adjacent mucosa of the same patients. The preliminary data suggest that enzymatic SOD in the gastric mucosa may play an important role in the pathogenic and healing processes of human peptic ulcers.
...
PMID:Changes in superoxide dismutase activity in the gastric mucosa of peptic ulcer patients. 162 68

Airway inflammation with human polymorphonuclear leukocytes (PMNs) may play an important role in the pathophysiology of bronchial asthma. Superoxide anion (O2-) and other active oxygen species derived from PMNs cause tissue damage. To evaluate the effects of antiasthma drugs on airway inflammation or antioxidative actions due to the inhibition of O2- generation, we investigated the effects of antiallergic drugs, beta-adrenergic agonists, theophylline and corticosteroids, on the in vitro generation of O2- by human PMNs, using a chemiluminescence (CL) method dependent on a Cypridina luciferin analog (MCLA), a highly sensitive and specific CL probe for O2-. We found that azelastine, one of the antiallergic drugs, and isoproterenol inhibited FMLP-induced O2- generation in a dose-dependent fashion, whereas the other drugs exhibited no such inhibitory action except at very high concentrations. Furthermore, we found that isoproterenol inhibited O2- generation from the hypoxanthine-xanthine oxidase system (an O2(-)-generating system) in a dose-dependent fashion, unlike azelastine and the other drugs. These results suggest that azelastine and isoproterenol inhibit the process of O2- generation from PMNs, while isoproterenol also scavenges O2-. These drugs may be beneficial in the treatment of airway inflammation due to O2- generation in bronchial asthma.
...
PMID:Effects of antiasthma drugs on superoxide anion generation from human polymorphonuclear leukocytes or hypoxanthine-xanthine oxidase system. 166 88

The Cypridina luciferin analog, 2-methyl-6-phenyl-3,7-dihydroimidazo[1,2-a]pyrazin-3-one (CLA), in Hanks' balanced salt solution, emitted a weak luminescence which was not affected by superoxide dismutase or catalase and was not augmented by resting human granulocytes. In contrast, activated granulocytes caused a dramatic increase in the luminescence of CLA. The light emission by CLA in the presence of activated granulocytes was inhibited by superoxide dismutase, but not by catalase or benzoate. Azide at 0.5 mM did not inhibit light emission significantly. These results indicate that O2-, rather than H2O2, HO., singlet oxygen, or HOCl, was the agent responsible for eliciting the chemiluminescence of CLA. Moreover, the intensity of light emission by CLA correlated with the rate of production of O2- either by activated neutrophils or by the xanthine oxidase reaction.
...
PMID:Chemiluminescence probe with Cypridina luciferin analog, 2-methyl-6-phenyl-3,7-dihydroimidazo[1,2-a]pyrazin-3-one, for estimating the ability of human granulocytes to generate O2-. 303 Jan 58

Membrane lipid peroxidation has been suggested to participate in the nigral degeneration of Parkinson's disease. In the present study, we demonstrate that bromocriptine inhibits lipid peroxidation in phospholipid liposomes induced by dopa and iron complexes. Because this lipid peroxidation is not mediated by active oxygen species, antioxidant properties of bromocriptine do not seem to be derived from radical scavenging effects in our experimental conditions. Bromocriptine had no scavenging effect on superoxide produced by hypoxanthine-xanthine oxidase when determined by the chemiluminescence assay using MCLA, a Cypridina luciferin analog, as a probe.
...
PMID:Inhibitory effects of bromocriptine on phospholipid peroxidation induced by dopa and iron. 774 68

Eleven new coelenterazine analogs containing the 3,7-dihydroimidazo[1,2-alpha]pyrazin-3-one structure were synthesized. The superoxide-triggered chemiluminescence of these compounds was investigated using the hypoxanthine-xanthine oxidase system in comparison with four known compounds. The results showed that an alkyl substitution at the position 5 of the imidazopyrazinone ring causes a drastic decrease in the superoxide-dependent chemiluminescence intensity, whereas a dimethylene bridge added between the position 5 and the phenyl group bound to the position 6 dramatically increases the luminescence intensity, indicating the potential usefulness of this type of compound as a probe for superoxide anion. The luminescence intensity of the bridged analog was 33 times greater than that of MCLA [2-methyl-6-(4-methoxyphenyl)-3, 7-dihydroimidazo[1,2-alpha]pyrazin-3-one], the most sensitive superoxide probe of Cypridina luciferin-type. Two of the analogs synthesized, each with a covalently bound cyclodextrin, had a good solubility in water, an advantage in actual use. Moreover, one of them having a beta-cyclodextrin group showed a unique property; its luminescence was little affected by various substances in the environment.
...
PMID:Coelenterazine analogs as chemiluminescent probe for superoxide anion. 919 6

Human serum albumin (HSA) is being considered as an alternate media for sperm enrichment in assisted reproductive technology (ART) because of recent concern with the use of Percoll. In this study, we compared HSA and Percoll for 1) sperm recovery, 2) reactive oxygen species scavenging potential, and 3) effects on total oxidative stress to spermatozoa. The spermatozoa-enriched fractions obtained from Percoll (80%:40%) and HSA (12%) were monitored for sperm motility, viability, hypoosmotic swelling test (HOST), and adenosine triphosphate (ATP) levels. The effect of superoxide anions (O2.-) on donor human spermatozoa was observed in the presence of either HSA or Percoll media. A combination of luminol and the Cypridina luciferin analog 2-methyl-6-(4-methoxyphenyl)-3,7-dihydroimidazo(1,2-alpha)pyraz in-3-one hydrochloride was used as a highly sensitive chemiluminescence probe in our hypoxanthine and xanthine oxidase-based assay for O2.-. Sperm membrane total oxidative stress was determined by measuring levels of the prostanoid 8-iso-Prostaglandin F2alpha (8-iso-PGF2alpha). Significant differences in sperm parameters between the Percoll-enriched spermatozoa (motility 60%+/-4%, viability 56%+/-6%, and HOST 73%+/-7%) and those enriched with HSA (motility 84%+/-5%, viability 85%+/-4%, and HOST 84%+/-3%; P < 0.01) were observed. Adenosine triphosphate levels were significantly higher, by almost 50%, in samples processed with HSA than with Percoll (P=0.03). The dismutation rate of O2.- in HSA (slope -6.8) was significantly lower than in Percoll (slope -87.0; P < 0.01). Sperm motility and ATP levels decreased at a slower rate after treatment with O2.- in the presence of HSA when compared to Percoll; moreover, spermatozoa in HSA regained partial motility after 2 hours, whereas spermatozoa in Percoll were immobilized. No significant differences in 8-iso-PGF2alpha levels in spermatozoa enriched by either HSA or Percoll were observed. We conclude that the HSA sperm enrichment procedure improves the recovery of higher quality spermatozoa compared to Percoll and, because of its antioxidant properties, may be useful in processing high leukospermia semen samples for ART purposes.
...
PMID:Antioxidant potential of human serum albumin: role in the recovery of high quality human spermatozoa for assisted reproductive technology. 973 43

Superoxide anion-triggered chemiluminescence of Cypridina luciferin analogue (CLA), 2-methyl-6-phenyl-3,7-dohydroimidazo[1,2-alpha]pyrazin-3-one, is enhanced by non-ionic detergents such as Tween 20, Triton X-100 and Tween 80. At the concentration of 0.6% (v/v) the largest increase (2.7-fold) of CLA light intensity was obtained with Tween 20, followed by Tween 80 and Triton X-100. Using this detergent-amplified CLA chemiluminescence, the detection limits of xanthine and xanthine oxidase were examined at pH 7.4 and reinvestigated at pH 5.5. At pH 5.5, concentrations of xanthine and xanthine oxidase as low as 5 nmol/L and 3.85 x 10(-7) U/mL, respectively, could be accurately determined, whereas, under the experimental conditions used, at pH 7.4 the lowest concentrations of xanthine and xanthine oxidase detectable were 10 nmol/L and 3.85 x 10(-6) U/mL. The lowest detectable values of xanthine and xanthine oxidase obtained at pH 5.5 are about 400 and 10 times lower than those previously reported. The detection limit of xanthine (5 nmol/L) by this chemiluminescent-based method is about 200 and 20 times more sensitive than the determination of xanthine by enzymatic means or by HPLC with detection limits of 1 micromol/L and 0.1 micromol/L, respectively. Our data suggest that this chemiluminescent probe can detect concentrations of superoxide anion below the nanomolar range.
...
PMID:Enhanced sensitivity of Cypridina luciferin analogue (CLA) chemiluminescence for the detection of *O2(-) with non-ionic detergents. 1118 Jun 58

Cypridina luciferin analogs have been widely used as a specific chemiluminescence probe for the detection of superoxide anion (O2-) and singlet oxygen (1O2). However, light emission during the reaction of Cypridina luciferin analogs and other active oxygen species (AOS) has not been reported in detail. Therefore, we re-evaluated 2-methyl-6-(p-methoxyphenyl)-3,7-dihydroimidazo[1,2-a]pyrazine-3-one (MCLA), one of the Cypridina luciferin analogs, as a chemiluminescence probe to detect various AOS. MCLA-dependent chemiluminescence was observed when MCLA was incubated with the following systems; 1) hypoxanthine plus xanthine oxidase (O2-), 2) thermolysis of endoperoxide (1O2), 3) hydrogen peroxide plus ferrous ion (hydroxyl radical), 4) ferrous ion, 5) thermolysis of azo compound (alkyl peroxyl radical) and 6) hydrogen peroxide. Superoxide dismutase inhibited MCLA-dependent chemiluminescence observed during ferrous ion-induced decomposition of hydrogen peroxide. Alkyl peroxyl radical reacted with MCLA, but light was not emitted when the concentration of MCLA was high. These results suggest that radicals, except O2-, appeared not to be direct inducers of MCLA-dependent light emission. In summary, MCLA-dependent chemiluminescence was induced by various AOS in addition to O2- and 1O2, but active species must be O2- and 1O2 in many cases. These points should be appreciated when Cypridina luciferin analogs, such as MCLA, are used for the detection of AOS.
...
PMID:Reestimation of Cypridina luciferin analogs (MCLA) as a chemiluminescence probe to detect active oxygen species--cautionary note for use of MCLA. 1297 6

---