Biomaterial Database

Incorporation and metabolic conversion of cyanocobalamin by Ehrlich ascites carcinoma cells in vitro and in vivo. 1975

K Peirce, and T Abe, and B A Cooper

1. Cyano [57 Co] cobalamin bound to murine transcobalamin, associates with Ehrlich ascites carcinoma cells. Association was found to be dependent on temperature, and to require between 7.2 - 10-5 and 2 - 10-4 M ionized calcium. 2. Association was blocked by vinblastine and colchicine, but not cytochalasin, suggesting that microtubules may be involved in this phenomenon. 3. Although irreversible association of radioactivity with cells was observed within minutes, appearance of significant radioactivity associated with the intracellular B12 binder, and conversion of cyanocobalamin to methyl- and 5'deoxyadenosylcobalamin required more than 18 h of incubation. 4. A pool of free vitamin B12 was found in cell extracts. This was composed of metabolically-active cobalamins characteristic of the interior of the cell, and not of cyanocobalamin recently incorporated. 5. Incorporation of 57Co-labelled vitamin B12 by these cells involves two major processes: a rapid irreversible association of transcobalamin-B12 complex following reaction with a presumably calcium-dependent receptor, and a much later entry of vitamin into the cytoplasm to become exposed to enzymes and associated with an intracellular binder.

UI	MeSH Term	Description	Entries
D008870	Microtubules	Slender, cylindrical filaments found in the cytoskeleton of plant and animal cells. They are composed of the protein TUBULIN and are influenced by TUBULIN MODULATORS.	Microtubule
D001798	Blood Proteins	Proteins that are present in blood serum, including SERUM ALBUMIN; BLOOD COAGULATION FACTORS; and many other types of proteins.	Blood Protein,Plasma Protein,Plasma Proteins,Serum Protein,Serum Proteins,Protein, Blood,Protein, Plasma,Protein, Serum,Proteins, Blood,Proteins, Plasma,Proteins, Serum
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D002286	Carcinoma, Ehrlich Tumor	A transplantable, poorly differentiated malignant tumor which appeared originally as a spontaneous breast carcinoma in a mouse. It grows in both solid and ascitic forms.	Ehrlich Ascites Tumor,Ascites Tumor, Ehrlich,Ehrlich Tumor Carcinoma,Tumor, Ehrlich Ascites
D002352	Carrier Proteins	Proteins that bind or transport specific substances in the blood, within the cell, or across cell membranes.	Binding Proteins,Carrier Protein,Transport Protein,Transport Proteins,Binding Protein,Protein, Carrier,Proteins, Carrier
D003037	Cobalt Radioisotopes	Unstable isotopes of cobalt that decay or disintegrate emitting radiation. Co atoms with atomic weights of 54-64, except 59, are radioactive cobalt isotopes.	Radioisotopes, Cobalt
D003078	Colchicine	A major alkaloid from Colchicum autumnale L. and found also in other Colchicum species. Its primary therapeutic use is in the treatment of gout, but it has been used also in the therapy of familial Mediterranean fever (PERIODIC DISEASE).	Colchicine, (+-)-Isomer,Colchicine, (R)-Isomer
D003572	Cytochalasins	11- to 14-membered macrocyclic lactones with a fused isoindolone. Members with INDOLES attached at the C10 position are called chaetoglobosins. They are produced by various fungi. Some members interact with ACTIN and inhibit CYTOKINESIS.
D003593	Cytoplasm	The part of a cell that contains the CYTOSOL and small structures excluding the CELL NUCLEUS; MITOCHONDRIA; and large VACUOLES. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)	Protoplasm,Cytoplasms,Protoplasms
D005293	Ferritins	Iron-containing proteins that are widely distributed in animals, plants, and microorganisms. Their major function is to store IRON in a nontoxic bioavailable form. Each ferritin molecule consists of ferric iron in a hollow protein shell (APOFERRITINS) made of 24 subunits of various sequences depending on the species and tissue types.	Basic Isoferritin,Ferritin,Isoferritin,Isoferritin, Basic