The nature of the biochemical lesion in avian renal riboflavinuria—II. The inherited change of a riboflavin-binding protein from blood and eggs

Winter, William P.; Buss, E. G.; Clagett, C. O.; Boucher, R. V.

doi:10.1016/0010-406x(67)90780-3

Cited by 83 publications

(28 citation statements)

References 12 publications

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“…However, the large amount of yellow riboflavin-binding protein present in the eggs from normal chickens complicated this approach. Hence, we used egg white from a strain of chickens that lack a functional riboflavin-binding protein and therefore do not accumulate significant riboflavin in their eggs (13,18,19). This greatly simplified the early phase of this project.…”

Section: Resultsmentioning

confidence: 99%

A Sulfhydryl Oxidase from Chicken Egg White

Hoober

Joneja

White

et al. 1996

Journal of Biological Chemistry

154

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A dimeric glycoprotein containing one FAD per ϳ80,000 M r subunit has been isolated from chicken egg white and found to have sulfhydryl oxidase activity with a range of small molecular weight thiols. Dithiothreitol was the best substrate of those tested, with a turnover number of 1030/min, a K m of 150 M, and a pH optimum of about 7.5. Oxidation of thiol substrates generates hydrogen peroxide in aerobic solution. Anaerobically, the ferricenium ion is a facile alternative electron acceptor. Reduction of the oxidase with dithionite or dithiothreitol under anaerobic conditions yields a two-electron intermediate (EH 2 ) showing a charge transfer band ( max 560 nm; ⑀ obs 2.5 mM ؊1 cm ؊1 ). Complete bleaching of the flavin and discharge of the charge transfer complex require a total of four electrons. Borohydride and catalytic photoreduction give the same spectral changes. EH 2 , but not the oxidized enzyme, is inactivated by iodoacetamide with alkylation of 2.7 cysteine residues/ subunit. These data indicate that the oxidase contains a redox-active disulfide bridge generating a thiolate to oxidized flavin charge transfer complex at the EH 2 level. Sulfite treatment does not form the expected flavin adduct with the native enzyme but cleaves the active site disulfide, yielding an air-stable EH 2 -like species. The close functional resemblance of the oxidase to the pyridine nucleotide-dependent disulfide oxidoreductase family is discussed.Sulfhydryl oxidases catalyze the oxidation of sulfhydryl groups to disulfides according to the following general reaction.They have been purified from a number of microbial and mammalian sources, but many questions concerning their mechanism and functional roles remain unresolved. Iron-dependent sulfhydryl oxidases have been found in bovine milk (1-3), in kidney (4), and in pancreatic zymogen granules (5). Coppercontaining sulfhydryl oxidases have been described from kidney and small intestine (6) and skin (7,8).A second distinct class of sulfhydryl oxidase is provided by FAD-dependent enzymes isolated from both rat seminal vesicles and fungal sources (9 -11). These careful studies show a range of diverse subunit composition and substrate specificity but clearly implicate the flavin cofactor in catalysis (9, 10). The present work reports the discovery and characterization of a flavoprotein sulfhydryl oxidase in chicken egg white.Our study began with the observation that egg white contains not only riboflavin (in the form of riboflavin-binding protein; Ref. 12) but also measurable levels of FAD (13). While the function of riboflavin-binding protein in the transport and storage of vitamin B 2 is well known (14), the reason for the presence of FAD in egg white was obscure. We first purified the FAD-containing protein by following its yellow color and subsequently identified it as a sulfhydryl oxidase active with a wide range of thiol substrates. This paper presents strong evidence for the involvement of a catalytically important disulfide as a second redox-active moiety in these flavin de...

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Section: Resultsmentioning

confidence: 99%

A Sulfhydryl Oxidase from Chicken Egg White

Hoober

Joneja

White

et al. 1996

Journal of Biological Chemistry

154

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“…These riboflavin-binding proteins are required for storage of ribofl avin in the egg for use by the developing embryo (276). Avian riboflavinuria, in which laying hens lose ribofl avin by glomeru lar fi ltration and produce eggs that do not mature beyond 10-14 days of incubation, has been shown to be caused by a single genetic defect that yields nonfunctional ribofl avin-binding proteins (276).…”

Section: Association With Binding (Carrier) Proteinsmentioning

confidence: 99%

Formation and Mode of Action of Flavoproteins

et al. 1981

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“…The gene product of the normal homozygous foul (RdRd), a riboflavin binding protein (RBP) found in the blood, egg yolk, and albumen of laying hens, is under the control of blood plasma estrogen legels (Clagett et al, 1970). In laying homozygous recessive hens, the absence of the functional carrier protein (Winter et al, 1967;Farrel et al, 1970b) leads to elevated riboflavin excretions in the urine (Cowan et al, 1964(Cowan et al, , 1965. Since the riboflavin is not transported to developing yolks nor present in deposited albumen during egg formation, the recessive embryo dies during the 12th to 14th day of incubation.…”

Section: Introductionmentioning

confidence: 99%

Avian Riboflavinuria

1975

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The riboflavin binding protein (RBP) content of individual egg components were followed through the development of fertilized eggs. Total proteins of the tissues were analyzed. The disappearance of RBP from the yolk and albumen occurred at the same rate as the total proteins. There was no evidence of any increase of free riboflavin nor degraded RBP in the yolk and albumen. Hence, it appears that the riboflavin was taken in by the embryo as the riboflavin-protein complex. The individual embryos showed some RBP accumulation through the first fourteen days of development. This may be an indication that the embryo is taking in the riboflavin-protein complex faster than riboflavin is utilized during the early stages of incubation. However, the beginning of a more rapid rate of growth at 13-14 days, was associated with the start of a gradual decline in the level of RBP in the embryo. This may suggest that the need for riboflavin exceeds the rate of transfer from the yolk and albumen reservoirs. RBP-riboflavin complex appears to be degraded after transfer to the embryo.

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The nature of the biochemical lesion in avian renal riboflavinuria—II. The inherited change of a riboflavin-binding protein from blood and eggs

Cited by 83 publications

References 12 publications

A Sulfhydryl Oxidase from Chicken Egg White

A Sulfhydryl Oxidase from Chicken Egg White

Formation and Mode of Action of Flavoproteins

Avian Riboflavinuria

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