IONIC INHIBITION OF GROWTH IN LACTOBACILLUS LEICHMANNII 313 AND ITS REVERSAL WITH VITAMIN B12

The identity of the compounds that together form the total microbiological vitamin B12 activity of cod-liver residue was determined by a fractionation procedure involving ion exchange, countercurrent distribution, partition chromatography, and microbiological assay. The presence of cyanocobalamin, hydroxocobalamin, and the desoxyribosides of thymine, uracil, hypoxanthine, xanthine, and guanine was demonstrated. The total vitamin B12 activity, as determined by microbiological assay with Lactobacillus leichmannii, and its distribution in cod-liver residue, were very similar to those of beef liver. Cod-liver residues may be used to replace beef liver in vitamin B12 preparations.

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Commercially-supplied binders for plasma cobalamin (vitamin B12), analysis--"purified" intrinsic factor, “cobinamide"-blocked R-protein binder, and non-purified intrinsic factor-R-protein binder--compared to microbiological assay.

Clinical Chemistry ◽

10.1093/clinchem/26.5.598 ◽

1980 ◽

Vol 26 (5) ◽

pp. 598-600 ◽

Cited By ~ 20

Author(s):

N P Kubasik ◽

M Ricotta ◽

H E Sine

Keyword(s):

Protein Binding ◽

Vitamin B12 ◽

Intrinsic Factor ◽

Microbiological Assay ◽

Binding Agents ◽

Lactobacillus Leichmannii

Abstract Recent evidence (Kolhouse et al., N. Engl. J. Med. 299: 785–792, 1978) demonstrates that commercial cobalamin (Vitamin B12) radioassay kits contain nonspecific R-protein binding agents that can give falsely normal results in patients who are actually cobalamin deficient. We tested three kits: with “purified” intrinsic factor as the binder, with intrinsic factor and the nonspecific R-protein sites blocked with “cobinamide,” and non-purified intrinsic factor-R-protein binder. Results with use of the first two compared well with those by a microbiological assay (Lactobacillus leichmannii) and are in harmony with clinical impressions.

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Vitamin B12, in Human Blood and Serum

Clinical Chemistry ◽

10.1093/clinchem/6.6.578 ◽

1960 ◽

Vol 6 (6) ◽

pp. 578-581 ◽

Cited By ~ 7

Author(s):

Herman Baker ◽

Oscar Frank ◽

Inez Pasher ◽

Harry Sobotka

Keyword(s):

Escherichia Coli ◽

Vitamin B12 ◽

Human Blood ◽

Euglena Gracilis ◽

Whole Blood ◽

Normal Subjects ◽

Lactobacillus Leichmannii

Abstract A comparison of microbiologic assays for vitamin B12 in whole blood or serum was carried out with four B12-requiring microorganisms, Escherichia coli 113-3, Lactobacillus leichmannii ATCC No. 7839, Euglena gracilis, strain Z, and Ochromonas malhamensis. B12 values in whole blood and serum for normal subjects are given. The value of microbiologic assays is discussed.

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