Abstract
A cobalamin-dependent N5-methyltetra-hydrofolate-homocysteine methyltransferase (methyl-transferase) was demonstrated in unfractioned extracts of human normal and leukemia leukocytes. Activity was substantially reduced in the absence of an added cobalamin derivative. Presumably, this residual activity reflects the endogeneous level of holoenzyme. Enzyme activity was notably higher in lymphoid cells than in myeloid cells. Thus, mean specific activities (+/-SD) were: chronic lymphocytic leukemia lymphocytes, 2.15+/-1.16; normal lymphocytes, 0.91+/-0.59; normal mature granulocytes, 0.15+/-0.10; chronic myelocytic leukemia granulocytes, barely detectable activity. Properties of leukocytes enzymes resembled those of methyltransferases previously studied in bacteria and other animal cells. Granulocytes and chronic myelocytic leukemia cells contain a factor or factors that inhibits Escherichia coli enzyme. The data suggest that the prominence of this cobalamin-dependent enzyme in lymphocytes and other mononuclear cell types may be related to their potential for cell division.
References
Sep 1, 1973·The Journal of Clinical Investigation·H B Kaltreider, S E Salmon
Oct 4, 1973·The New England Journal of Medicine·R I HandinW C Moloney
Dec 1, 1974·Archives of Biochemistry and Biophysics·R T TaylorJ J Hutton
Sep 1, 1973·Proceedings of the National Academy of Sciences of the United States of America·D KamelyR W Erbe
Mar 25, 1974·Biochemical and Biophysical Research Communications·H AsheR A Smith
Apr 1, 1974·Proceedings of the National Academy of Sciences of the United States of America·B C HalpernR A Smith
Jun 1, 1974·British Journal of Haematology·D J Perera, G D Pegrum
Jan 1, 1974·Annals of the New York Academy of Sciences·F T Valentine
May 1, 1973·Pediatric Research·G E GaullJ A Sturman
Feb 1, 1969·Archives of Biochemistry and Biophysics·R T Taylor, H Weissbach
Jan 1, 1972·Archives of Biochemistry and Biophysics·J H MangumJ A North
Sep 28, 1971·Biochemistry·J H Mangum, J A North
Sep 1, 1971·Archives of Biochemistry and Biophysics·J D FinkelsteinB J Harris
Apr 1, 1966·Proceedings of the Society for Experimental Biology and Medicine·M RachmilewitzJ Gross
Sep 1, 1969·Biochemistry·J H MangumJ A North
Apr 1, 1970·Analytical Biochemistry·J A Blair, K J Saunders
Oct 1, 1970·British Journal of Haematology·K C Das, A V Hoffbrand
Nov 1, 1970·Biochemical Medicine·S H MuddK R Hinds
Jan 1, 1971·Archives of Biochemistry and Biophysics·S S KerwarH Weissbach
Mar 28, 1966·Biochimica Et Biophysica Acta·K Simons, T Weber
Dec 1, 1963·The Journal of Clinical Investigation·J R BERTINOF M HUENNEKENS
Citations
Jun 1, 1990·American Journal of Hematology·J AbelsJ Lindemans
Jun 15, 1982·Experientia·D RozynkowaZ Rupniewska
Jan 8, 1981·Clinica Chimica Acta; International Journal of Clinical Chemistry·Y KanoF Takaku
Nov 1, 1992·Atherosclerosis·J WangJ F Lynch
Nov 1, 1987·Acta paediatrica Scandinavica·J ZittounC Griscelli
Apr 28, 2010·PloS One·Zhiqian TongYou Wan
Apr 16, 1984·Biochemical and Biophysical Research Communications·W S Beck, J Thorndike
Jun 20, 2018·Clinical and Applied Thrombosis/hemostasis : Official Journal of the International Academy of Clinical and Applied Thrombosis/Hemostasis·Eulo Lupi-HerreraVerónica Guarner-Lans
Oct 1, 1976·Postgraduate Medicine·L Kass
Sep 1, 1993·Arteriosclerosis and Thrombosis : a Journal of Vascular Biology·N P DudmanP Lundberg
Jul 1, 1983·European Journal of Cancer & Clinical Oncology·Y KanoF Takaku