[Methylcobalamin-dependent methylation of proteins during malignant degeneration].
A capacity of methylcobalamine (14CH3-B12) to methylate proteins from rat liver tissue and from Zajdela ascites hepatoma was studied. The rate of methylation using 14CH3B12 was compared with that of the universal donor of methyl groups--S-adenosyl-L-(methyl-14C[methionine], Ado-met)-14CH3-B12 methylated proteins from Zajdela ascites hepatoma 6-9-fold and proteins from liver tissue 50-60-fold more intensively as compared with Ado-met in vitro. The methylating ability of 14CH3-B12 depended on protein concentration. Liver proteins were methylated at the rate 2-2.5-fold higher than Zajdela ascites hepatoma proteins. At the same time, Ado-met was the most effective donor of 14CH3 groups for proteins of Zajdela ascites hepatoma. Heat treatment of proteins increased the rate of their methylation using 14CH2-B12 by 10-20%; when Ado-met was used the transfer of CH3 groups was decreased 2-5-fold.
D000818:Animals; D004789:Enzyme Activation; D008099:Liver / Q000201:enzymology; D008114:Liver Neoplasms, Experimental / Q000201:enzymology; D008297:Male; D008745:Methylation; D008780:Methyltransferases / Q000378:metabolism; D009363:Neoplasm Proteins / Q000378:metabolism*; D051381:Rats; D012436:S-Adenosylmethionine / Q000378:metabolism; D014805:Vitamin B 12 / Q000031:analogs & derivatives* / Q000378:metabolism
D009363:Neoplasm Proteins; D012436:S-Adenosylmethionine; C019476:mecobalamin; D008780:Methyltransferases; D014805:Vitamin B 12
Metilkobalaminzavisimoe metilitrovanie belkov pri malignizatsii.