Results 281 to 290 of about 43,643 (334)

Membrane transport of cobalamin

2022
A wide variety of organisms encode cobalamin-dependent enzymes catalyzing essential metabolic reactions, but the cofactor cobalamin (vitamin B12) is only synthesized by a subset of bacteria and archaea. The biosynthesis of cobalamin is complex and energetically costly, making cobalamin variants and precursors metabolically valuable.
Nijland, Mark, Martínez Felices, Jose M., Slotboom, Dirk J., Thangaratnarajah, Chancievan   +3 more
openaire   +2 more sources

Determination of Cobalamin and Related Compounds in Foods.

Journal of AOAC International, 2018
Cobalamin, also known as the red-colored vitamin B12, is found in animal-based foods such as meat, milk, and fish. Various cobalamin compounds are extracted from foods and converted into cyanocobalamin, which is most stable, to be analyzed by various ...
F. Watanabe, T. Bito
semanticscholar   +1 more source

Cobalamin Deficiency

2011
Cobalamin (Cbl, vitamin B12) consists of a corrinoid structure with cobalt in the centre of the molecule. Neither humans nor animals are able to synthesize this vitamin. Foods of animal source are the only natural source of cobalamin in human diet.
Wolfgang, Herrmann, Rima, Obeid
openaire   +2 more sources

Cimetidine and malabsorption of cobalamin

Digestive Diseases and Sciences, 1982
Cimetidine in a dosage of 1000 mg daily (200 mg t.i.d. plus 400 mg nocte) reduced the absorption of protein-bound cobalamin by peptic ulcer patients and normal subjects. However, cimetidine in a dosage of 400 mg at night had no significant effect, nor did tripotassium dicitratobismuthate in a dosage of 480 mg daily. Thus long-term administration of 400
M. T. Pheils, F. A. Bathur, G. G. Crane, R. S. Hilmer, A.M. Streeter, K. J. Goulston   +5 more
openaire   +3 more sources

High-pressure liquid chromatography of cobalamins and cobalamin analogs

Analytical Biochemistry, 1982
Abstract High-pressure liquid chromatography has been used to separate, identify, and quantitate 37 different cyanocobalamin analogs, including the most commonly occurring analogs that result from bacterial synthesis. This technique has also been used to simultaneously separate, identify, and quantitate five naturally occurring cobalamins that differ
Kenneth C. Van Horne, Mitchell Binder, J. Fred Kolhouse, Robert H. Allen   +3 more
openaire   +3 more sources

Cobalamin Absorption and Acquired Forms of Cobalamin Malabsorption

1989
Cobalamin (Cbl), or vitamin B12, cannot be synthesized in the human body, and the only possible source for this vitamin is thus the diet. Daily requirements are 1-3 µg [31]. Dietary sources are primarily animal proteins. Liver, mammalian kidneys, and seafood are especially rich in this vitamin. Meat, fish, milk, and dairy foods also contain vitamin B12,
D. Cattan, J. Belaïche
openaire   +2 more sources

Spectroscopic and Electrochemical Characterization of the Iron-Sulfur and Cobalamin Cofactors of TsrM, an Unusual Radical S-Adenosylmethionine Methylase.

Journal of the American Chemical Society, 2016
TsrM, an annotated radical S-adenosylmethionine (SAM) enzyme, catalyzes the methylation of carbon 2 of the indole ring of L-tryptophan. Its reaction is the first step in the biosynthesis of the unique quinaldic acid moiety of thiostrepton A, a ...
A. Blaszczyk, Alexey Silakov, Bo Zhang, S. J. Maiocco, N. Lanz, W. Kelly, S. Elliott, C. Krebs, S. Booker   +8 more
semanticscholar   +1 more source

Accumulation of NO2‐cobalamin in nutrient‐stressed ammonia‐oxidizing archaea and in the oxygen deficient zone of the eastern tropical North Pacific

Environmental Microbiology Reports, 2018
Cobalamin (vitamin B12 ) is a precious resource in natural systems that is produced by select prokaryotes and required by a broad range of organisms. In this way, the production of cobalamin reinforces numerous microbial interdependencies. Here we report
K. Heal, W. Qin, Shady A. Amin, A. Devol, James W. Moffett, E. Armbrust, David A. Stahl, A. Ingalls   +7 more
semanticscholar   +1 more source

Cobalamin and the Nervous System

New England Journal of Medicine, 1988
To the stalwart little band of investigators of vitamin B12 — now more rationally termed cobalamin — there is comfort in knowing that the stream of important scientific problems will never end.
openaire   +3 more sources

Cobalamin-binding proteins in normal and cobalamin-deficient older subjects

Annals of Clinical Biochemistry: International Journal of Laboratory Medicine, 2003
Background: The causes of cobalamin (vitamin B12) deficiency in older people are only partly understood. We investigated the role of the cobalamin-binding proteins and tested the hypothesis that low saturated transcobalamin concentration is an early marker of cobalamin deficiency.
Asselt, D.Z.B. van, Thomas, C.M.G., Segers, M.F.G., Blom, H.J., Wevers, R.A., Hoefnagels, W.H.L.   +5 more
openaire   +4 more sources