Studies on microheterogeneity of intracellular transcobalamins of blood cells in special reference to leukemia
Urai, H.; Yamaguchi, N.
Kobe Journal of Medical Sciences 31(1): 39-61
1985
ISSN/ISBN: 0023-2513 PMID: 3858604 Document Number: 266516
Transcoblamins (TC) in isolated myeloid cells were analyzed to clarify their intracellular conversions in the course of cellular maturation. By DEAE-cellulose column chromatography, sera of normal controls contained mainly transcobalamin II (TCII) and sera of cases with chronic mydlocytic leukemia [CML], mainly TCI and TCIII. As for intracellular TC, mostly TCIII was contained in mature granulocytes and mostly TCII in immature granulocytes including leukemic blast cells. TC were analyzed by thin layer agarose isoelectric focusing (IEF) gel electrophoresis, combined with autoradiography. Sera of normal controls contained mainly TC bands with isoelectric point (pI) value of 6 and sera of cases with CML, mainly TC bands with pI values of 3-4.5. Mature granulocytes contained mainly TC bands with pI values of 3-4.5, while immatrue granulocytes and leukemic cells contained TC bands with pI values of 4.5-5.0 in addition to TC bands with pI values of 3-4.5. After treatment with neuraminidase, TC in all of the myeloid cells, which were initially distributed widely in the pH range of 3-4.5 showed 2 or 4 TC bands with pI values of 5. The levels of neuraminidase in granulocytes decreased in proportion to their maturation. However, neuraminidase activities might not be related to the intracellular conversions of TC. TC with pI values of 5 found in leukemic cells and immature granulocytes, being sialylated in the course of cellular maturations, might be the precursors of TCI and TCIII. TCII fraction eluted from immature granulocytes is not considered a true TCII but the above precursor.