Riboflavin metabolism of cows and goats and rate of biosynthesis of riboflavin by the lactating goat

Crossland, Audrey; Owen, E.; Proudfoot, R.

doi:10.1079/bjn19580043

Cited by 18 publications

(10 citation statements)

References 26 publications

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“…Alkaline phosphatase was estimated by the method of Kay, Aschaffenburg & Neave (4), and total riboflavin in milk by the method of Bessey, Lowry & Love (5) in which the fluorescence of the riboflavin was measured directly in the supernatant liquid from a precipitation of the milk with trichloroacetic acid. After neutralization with K 2 HP0 4 , the fluorescence of the solution was measured in a laboratory-built fluorimeter of the Lowry (6) type as described by Crossland, Owen & Proudfoot (7). To estimate the partition of riboflavin between the free and bound forms a chromatographic separation was made.…”

Section: Methodsmentioning

confidence: 99%

Parition of riboflavin in cow's milk

Modi

Owen

Darroch

1959

Journal of Dairy Research

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Chanda, McNaught & Owen(i) found that injection of thyroxine increased the ratio of bound to free thiamine (vitamin B x ) in the milk of the cow, and Thompson (2) found that ingestion of iodinated casein had the same effect. Injection of thiouracil(i) decreased this ratio, but neither thyroxine nor thiouracil affected the total output of thiamine in the milk. The increase of the bound form engendered by thyroxine was due partly to an increase in thiamine pyrophosphate (cocarboxylase) and partly to an increase in proteinbound thiamine. The riboflavin of cow's milk is partly free and partly combined in a non-ultrafiltrable form (3). The bound riboflavin is in the form of flavinadenine dinucleotide (FAD) for when set free, presumably from protein, by trichloroacetic acid, it behaves like FAD on chromotography or electrophoresis. The following experiments were done to see whether injection of thyroxine affects the partition of riboflavin between its free and its bound forms in cow's milk. EXPERIMENTAL Six Ayrshire cows, 1 month calved, were used. The experiment was divided into Period 1 of 20 days, Period 2 of 14 days and Period 3 of 20 days. During Period 2 three of the cows each received subcutaneously 6-2 mg. L-thyroxine (sodium salt) daily. Total and bound riboflavin were determined in the milk. Milk yields and alkaline phosphatase in the milk and the heart rate of each cow were recorded to show whether the thyroxine was producing its expected physiological effects.Heart rate was recorded at the time of afternoon milking each day. Alkaline phosphatase was estimated by the method of Kay, Aschaffenburg & Neave (4), and total riboflavin in milk by the method of Bessey, Lowry & Love (5) in which the fluorescence of the riboflavin was measured directly in the supernatant liquid from a precipitation of the milk with trichloroacetic acid. After neutralization with K 2 HP0 4 , the fluorescence of the solution was measured in a laboratory-built fluorimeter of the Lowry (6) type as described by Crossland, Owen & Proudfoot(7). To estimate the partition of riboflavin between the free and bound forms a chromatographic separation was made. The milk was treated in the cold with trichloroacetic acid to liberate FAD from its combination with protein.The precipitate was rejected, and the remaining liquid was neutralized with K 2 HPO 4 and extracted with phenol. Addition of ether to the phenol threw out an aqueous phase containing all the riboflavin and the FAD. Residual ether in the separated aqueous phase was evaporated by warming in hot water. Portions of the aqueous extract were chromatographed on Whatman no. 31 paper as described by Crossland et al(l). The riboflavin spot was then eluted and measured fluorimetrically. The difference between the total and that eluted from the chromatogram gave a measure of riboflavin bound to protein as FAD.

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Section: Methodsmentioning

confidence: 99%

Parition of riboflavin in cow's milk

Modi

Owen

Darroch

1959

Journal of Dairy Research

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“…Dick (1953) showed that both the absorption of molybdate and its excretion in urine are much enhanced when the diet of the sheep contains sulphate. We have found, however, that xanthine oxidase continues to be present in the milk of the goat when molybdate is omitted from the salt mixture of Crossland et al (1958) at the same time as nearly all the sulphate in it is replaced by chloride. While receiving such a diet goats were each dosed with I g sodium tungstate (Na,W0,.2H20) which, presumably by competition with molybdate, inhibits the formation of xanthine oxidase in both the rat and the chick (Higgins, Richert & Westerfeld, 1956).…”

Section: Abstracts Of Communications I959mentioning

confidence: 91%

Abstracts of Communications

1959

Proc. Nutr. Soc.

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in cow's milk but not in human milk. We have also examined the milk of goats, sheep, pigs and a mare. The milks of all the ruminants, cow, sheep and goat, contained xanthine oxidase. Milk from the sow and the mare resembled human milk in being devoid of the enzyme. To test whether these differences had a dietary basis the rabbit, which is herbivorous but non-ruminant, was examined and each of two does gave milk which contained xanthine oxidase. Oxytocin had to be used to obtain milk from the sow and rabbit. Analyses by an adaptation (Owen, 1957) of the dithiol method of Clark & Axley (1955) showed the presence of 30-60 pg molybdenum/l. in cow's milk. In human milk and pig's milk ashed with H,SO, + HC10, the molybdenum dithiol colour at 680 mp in the iso-amyl acetate extract was no greater than the blank for the reagents used. The failure to secrete xanthine oxidase may be a consequence either of a small intake of molybdenum or of an inability of the mammary epithelium of the non-secreting species to metabolize molybdenum.

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“…Extraction of metabolite from urine samples. Urine was collected in amber bottles from a volunteer for a total of 48 h after ingestion of I g 7,8-dimethyl-1o-(~-ribityl-$-phosphate) isoalloxazine (flavinomononucleotide, FMN) in water, The fluorescent urines were combined and the isoalloxazines present were concentrated by phenol extraction (Crossland, Owen & Proudfoot, 1958). The phenol concentrate was extracted several times with twice its volume of a chloroform-methanol mixture (3 : I, by volume) and the extracts were combined and concentrated on a rotatory evaporator.…”

Section: E X P E R I M E N T a Lmentioning

confidence: 99%

Degradation of riboflavin by alimentary bacteria of the ruminant and man: production of 7,8-dimethyl-10-carboxymethylisoalloxazine

West

Oiven

1973

Br J Nutr

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I . A new product of the bacterial degradation of riboflavin has been isolated from fermentations in vitro of mixtures of either rumen bacteria or caecal bacteria with excess of the vitamin.2 . This product has been identified as ~,8-dimethyl-ro-carboxymethylisoalloxazine and has also been shown to occur in the urine of ruminants and man.3. The bacterial formation of this compound is cornparedwith the bacterial formation of other isoalloxazines previously identified in similar incubation mixtures, and is discussed in relation to the factors influencing the mode of degradation of riboflavin.

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Riboflavin metabolism of cows and goats and rate of biosynthesis of riboflavin by the lactating goat

Cited by 18 publications

References 26 publications

Parition of riboflavin in cow's milk

Parition of riboflavin in cow's milk

Abstracts of Communications

Degradation of riboflavin by alimentary bacteria of the ruminant and man: production of 7,8-dimethyl-10-carboxymethylisoalloxazine

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