An Immunochemical Study of the Changes in Chicken Liver Xanthine Dehydrogenase Activity during Dietary Adaptation

Itoh, Roichi; Nishino, Tokuzo; Usami, Chikako; Tsushima, Kenji

doi:10.1093/oxfordjournals.jbchem.a132107

Cited by 27 publications

(9 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Previous studies have investigated the effects of specific variations of diet on chicken XD activity (Scholz and Featherson, 1968;Itoh et al, 1978) as well as the developmental patterns of XD in the embryo and the posthatching period (Lee and Fisher, 1971). These stud-ies have focused on liver, pancreas, intestine, and kidney tissues, but to our knowledge, there is no information on XD distribution in other chicken tissues.…”

Section: Introductionmentioning

confidence: 99%

Determination of xanthine oxidoreductase activity in broilers: Effect of pH and temperature of the assay and distribution in tissues

et al. 2009

View full text Add to dashboard Cite

Xanthine oxidoreductase (XOR) is the enzyme responsible for the synthesis of uric acid, which exists primarily in the dehydrogenase form in birds. Uric acid is the major end product of the metabolism of nitrogen-containing compounds in birds and it functions as an antioxidant to reduce oxidative stress. Despite the importance of this enzyme, the tissue distribution of XOR in physiologically normal chickens is not well known. In this study, we analyzed XOR activity in extracts of 8 tissues from broilers at 7 and 10 wk of age. No differences in XOR activity due to the age were found in any tissue. Liver and kidney showed the greatest activity, that in the kidney being about 89% of the activity in the liver. Enzyme activity in intestine and pancreas was about 60 and 37% of that in the liver. All breast muscle, heart, and lung samples showed enzyme activity, but values were only 3.0, 1.2, and 0.6% of those found in the liver. Traces of enzyme activity were also detected in 3 out of 10 brain samples, and no activity was found in the plasma. Our results show that XOR distribution in chickens differs from that in mammals, in which the highest levels have been found in liver and intestine. An additional objective was the evaluation of the effect of pH (7.2, 7.7, 8.2, and 8.7) and temperature (25 and 41 degrees C) on the enzyme activity in liver and kidney samples. Temperature had a similar effect on both tissues, with the activity at 25 degrees C being about 30% of that measured at 41 degrees C. At 41 degrees C, the enzyme activity in liver and kidney decreased quadratically as pH decreased from 8.7 to 7.2. The highest activity in kidney was measured at pH 8.2, although there were no differences between enzyme activities at pH 8.7 or 8.2 in the liver. Our results indicate that the optimum pH of the enzyme in chicken liver and kidney is around 8.2.

show abstract

Section: Introductionmentioning

confidence: 99%

Determination of xanthine oxidoreductase activity in broilers: Effect of pH and temperature of the assay and distribution in tissues

et al. 2009

View full text Add to dashboard Cite

show abstract

“…The desulfo enzyme is also known to be present in purified enzyme preparations and has been considered to be a preparation or storage artifact (9). However, the enzyme purified from the livers of chickens fed a high-protein diet has a higher specific activity (10) and, furthermore, the molecular activity changes with the diet (11). This suggests that a mechanism-exists in vivo whereby interconversion between the sulfo and desulfo forms may be effected.…”

mentioning

confidence: 99%

Reversible interconversion between sulfo and desulfo xanthine oxidase in a system containing rhodanese, thiosulfate, and sulfhydryl reagent.

Nishino¹,

Usami²,

Tsushima³

1983

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

The desulfo form of milk xanthine oxidase (xanthine:oxygen oxidoreductase, EC 1.2.3.2) was reactivated by incubation with rhodanese (thiosulfate:cyanide sulfurtransferase, EC 2.8.1.1), thiosulfate, and sulfhydryl reagent; 50% of full aetivity was recovered. No further reactivation occurred with additional incubation. It was also found that native enzyme in-the sulfo form with full activity was inactivated by incubation with. the same system, down' to half of full activity and no further inactivation occurred. After these incubations the enzyme was found to be a mixture of functional and nonfunctional enzymes based on spectral changes with xanthine, on [ The molybdenum-containing enzymes xanthine oxidase (xanthine:oxygen oxidoreductase,. EC 1.2.3.2) (1), xanthine dehydrogenase (2, 3), and aldehyde oxidase (4) can be converted into inactive forms by treatment with cyanide, which results in the release of an essential sulfur atom as thiocyanate. Recent advances in characterization of the desulfo enzyme show that. the. sulfur atom is present as molybdenum sulfide (5-8). The desulfo enzyme is also known to be present in purified enzyme preparations and has been considered to be a preparation or storage artifact (9). However, the enzyme purified from the livers of chickens fed a high-protein diet has a higher specific activity (10) and, furthermore, the molecular activity changes with the diet (11). This suggests that a mechanism-exists in vivo whereby interconversion between the sulfo and desulfo forms may be effected.The successful separation of sulfo and desulfo enzymes by affinity chromatography (12) (13); specific activity was determined to be 2,630 dpm/nmol by measurement of radioactivity and absorbance at 242 nm.Milk xanthine oxidase was purified by the method of Ball (14) with some modifications. Removal of nonfunctional enzyme was achieved by folate affinity chromatography according to the method of Nishino et at (12). Desulfo enzyme was prepared essentially by the method of Massey et at (1); fully active enzyme was treated with 30 mM KCN for 10 min at 250C and was dialyzed extensively against 0.1 M pyrophosphate, pH 8.5/ 0.2 mM EDTA. Xanthine oxidase activity was measured spectrophotometrically at 295 nm in 0.1 mM xanthine/0.1 M pyrophosphate, pH 8.5, at 250C (15). Enzyme concentration was determined from absorbance at 450 nm by using a value of 37,800 M-'cm-' for the molar absorptivity of enzyme-bound FAD (15). Radioactivity was measured in a Packard Tri-Carb liquid scintillation counter (model 2660) and a counting solution of Aquasol-2 (New England Nuclear). Absorbance spectra were recorded on a Cary 17 or Aminco-Chance DW-2a spectrophotometer.The standard reaction 'conditions for activation of desulfo xanthine oxidase or for inactivation of sulfo xanthine oxidase were as follows. Desulfo enzyme (final A4w, 0.2-0.4) with an activity-to-flavin ratio (AFR) of 0-5 prepared by cyanide treatment or native sulfo enzyme (final A40, 0.2-0.4) prepared by folate affinity chromatography was incubated at 370...

show abstract

“…It is conceivable that the enzyme might be subjected to some forms of post-translational activation. Desulpho-sulpho enzyme conversion of bovine milk XOR, with resultant activation, has been effected in vitro by incubation of reduced enzyme with sulphide ion [19], and in vivo enzymic activation in response to increased protein diet has been attributed to desulpho-sulpho conversion in chickens [20] and rats [Zl]. We ourselves have evidence of similar post-translational up-regulation of XOR in the human epithelial cell line, HB4a [ZZ].…”

Section: Mechanism For Production Of Ros During Ischaemia-reperfusionmentioning

confidence: 89%

Human xanthine oxidoreductase: in search of a function

Harrison

1997

Biochemical Society Transactions

View full text Add to dashboard Cite

An Immunochemical Study of the Changes in Chicken Liver Xanthine Dehydrogenase Activity during Dietary Adaptation

Cited by 27 publications

References 0 publications

Determination of xanthine oxidoreductase activity in broilers: Effect of pH and temperature of the assay and distribution in tissues

Determination of xanthine oxidoreductase activity in broilers: Effect of pH and temperature of the assay and distribution in tissues

Reversible interconversion between sulfo and desulfo xanthine oxidase in a system containing rhodanese, thiosulfate, and sulfhydryl reagent.

Human xanthine oxidoreductase: in search of a function

Contact Info

Product

Resources

About