PMID- 7599160
OWN - NLM
STAT- MEDLINE
DCOM- 19950810
LR  - 20190610
IS  - 0006-3002 (Print)
IS  - 0006-3002 (Linking)
VI  - 1244
IP  - 2-3
DP  - 1995 Jun 9
TI  - The dynamics of cobalamin utilization in L-1210 mouse leukemia cells: a model of 
      cellular cobalamin metabolism.
PG  - 395-403
AB  - The uptake and metabolism of cobalamin (Cbl) has been studied in L-1210 murine 
      leukemia cells propagating in vitro. Extracellular Cbl (protein bound and free) 
      and intracellular Cbl (protein bound and free) were determined after culturing 
      L-1210 cells in the presence of [57Co]cyanocobalamin (CN-Cbl) bound to 
      transcobalamin II (transcobalamin, TC). The intracellular pool of free [57Co]Cbl 
      increased during the first 24 h of culture and a substantial fraction of this 
      free pool was effluxed from the cell to the medium. Upon depletion of 
      extracellular TC-[57Co]CN-Cbl, the intracellular concentration of free Cbl 
      decreased as did the efflux of Cbl to the medium. Internalized [57Co]CN-Cbl was 
      converted to hydroxocobalamin (OH-Cbl), methylcobalamin (Me-Cbl) and 
      5'-deoxyadenosylcobalamin. These Cbl forms were found in both soluble 
      (cytoplasmic) and insoluble (membrane) fractions. Intracellular protein-bound 
      [57Co]Cbl fractionated with methionine synthase (MS) and methylmalonyl-CoA mutase 
      (MU) activity. The major form of Cbl associated with the two enzymes was OH-Cbl. 
      Cells propagated in medium containing N5-methyltetrahydrofolate and homocysteine 
      showed a substantial increase in MS activity which paralleled the increase in the 
      intracellular concentration of Me-Cbl and the Cbl bound to the enzyme.
FAU - Quadros, E V
AU  - Quadros EV
AD  - Division of Hematology/Oncology V.A. Medical Center, Brooklyn, NY 11209, USA.
FAU - Jacobsen, D W
AU  - Jacobsen DW
LA  - eng
PT  - Journal Article
PL  - Netherlands
TA  - Biochim Biophys Acta
JT  - Biochimica et biophysica acta
JID - 0217513
RN  - 0 (Cobalt Radioisotopes)
RN  - 0 (Cobamides)
RN  - 0 (Culture Media, Conditioned)
RN  - 0 (Transcobalamins)
RN  - BR1SN1JS2W (mecobalamin)
RN  - EC 2.1.1.13 (5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase)
RN  - EC 5.4.99.2 (Methylmalonyl-CoA Mutase)
RN  - F0R1QK73KB (cobamamide)
RN  - P6YC3EG204 (Vitamin B 12)
RN  - Q40X8H422O (Hydroxocobalamin)
SB  - IM
MH  - 5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase/metabolism
MH  - Animals
MH  - Cobalt Radioisotopes
MH  - Cobamides/metabolism
MH  - Culture Media, Conditioned
MH  - Hydroxocobalamin/metabolism
MH  - Leukemia L1210/*metabolism
MH  - Methylmalonyl-CoA Mutase/metabolism
MH  - Mice
MH  - Transcobalamins/metabolism
MH  - Vitamin B 12/analogs & derivatives/*metabolism
EDAT- 1995/06/09 00:00
MHDA- 1995/06/09 00:01
CRDT- 1995/06/09 00:00
PHST- 1995/06/09 00:00 [pubmed]
PHST- 1995/06/09 00:01 [medline]
PHST- 1995/06/09 00:00 [entrez]
AID - 0304-4165(95)00037-C [pii]
AID - 10.1016/0304-4165(95)00037-c [doi]
PST - ppublish
SO  - Biochim Biophys Acta. 1995 Jun 9;1244(2-3):395-403. doi: 
      10.1016/0304-4165(95)00037-c.