A New Concept of the Physiological Role of Vitamin B12

Heathcote, J. G.; Mooney, F.S.

doi:10.1111/j.2042-7158.1958.tb10348.x

Cited by 22 publications

(7 citation statements)

References 75 publications

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“…Muscle-B,, is not liberated and is therapeutically inactive (3, 4). I t is possible that dialyzable B,,, liberated by enzymes and possibly conjugated with peptides (9,10) is absorbed even in the absence of I. F.…”

Section: Discussionmentioning

confidence: 99%

“…Defining bound B,, as nondialyzable, crystalline B,, is unbound, but vitamin B,, as it occurs in nature and in human food is, as will be shown, largely bound. Although the role played by gastric proteolysis in the absorption of vitamin B,, has been discussed many times (2,9, 21,(24)(25)(26), the effect of proteinases on bound B,, seems to have been little studied (6, 7, 8, 23). The effect on bound B,, of some enzymes partaking in the gastrointestinal digestion of food will be described in this paper.…”

mentioning

confidence: 99%

“…times (2,9,21,(24)(25)(26), the effect of proteinases on bound B,, seems to have been little studied (6,7,8,23). The effect on bound B,, of some enzymes partaking in the gastrointestinal digestion of food will be described in this paper.…”

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confidence: 99%

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Effect of Digestive Enzymes on Bound Vitamin B₁₂¹

Reizenstein¹

1959

Journal of Internal Medicine

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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Effect of Digestive Enzymes on Bound Vitamin B₁₂¹

Reizenstein¹

1959

Journal of Internal Medicine

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“…Al though we have not examined as yet the clinical activity of our B12-binding principles in per nicious anemia patients, they are the first microbial B12-binders which augment the B12 uptake by IMH. Should our materials prove to be effective in pernicious anemia patients, it would give a partial support to the proposal of Heathcote and Mooney (39,40) who discredit IF. Their idea is based on the observations that their B12-peptides obtained from Strepto myces and Propionibacterium were effective in treating pernicious anemia.…”

Section: Discussionmentioning

confidence: 99%

Attachment of the B12-Binding Principles Obtained from Lactobacillus leichmannii to Intestinal Mucosa Homogenates

Sasaki

1971

J. Vitaminol

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The B12-binding principles isolated from cellular components of Lacotobacillus leichmannii ATCC 7830 were studied for the activity to augment vitamin B12 uptake by intestinal mucosa homogenates (IMH) of the guinea pig, hog, rat, hamster, and man. It was found that the uptake of B12 by the IMH of these species was markedly augmented by these principles. The degrees of augmenta tion were much greater than that effected by the homologous intrinsic factor (IF). The IF-augmented uptake of B12 by guinea pig IMH was reduced when calcium ion was deleted from the incubation medium, while the deletion of calcium ion had no effect on the uptake augmented by the B12-binding principle. Boiling of IMH for 10min completely abolished the IF-augmented uptake of B12 but the effect of the B12-binding principle was not affected at all. These results indicate that difference exists between IF and the B12-binding principle in the mode of attachment to the adsorptive surface of the small intestine. The B12 uptake by everted sacs prepared from the distal portion of guinea pig ileum was slightly augmented by guinea pig IF but not by the B12-binding princinciple. However, the mucous materials liberated into the medium from the everted sacs during incubation took up large amounts of B12 in the presence of the B12 binding principle as well as IF.

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“…This substance was not present in the serum of untreated patients or of healthy subjects. Possibly Schwartz's inhibiting substance is analogous with those produced experi mentally by Taylor & Morton (40), but, as both groups were working with relatively crude preparations, it is impossible to know whether the antigen was intrinsic factor itself, or accompanying protein also concerned in the absorption of vitamin B12• A new concept regarding the absorption of vitamin B12 has recently been put forward by Heathcote & Mooney (42,43), who point out that vitamin B12 is usually present in food in a bound form not assimilable until proteo lyzed to what they suggest may be a dialyzable vitamin B12-peptide complex. They claim to have produced such a complex by fermentation of a Strepto myces mutant and consider it the most effective oral preparation yet de scribed for the treatment of pernicious anaemia.…”

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confidence: 96%