Human beta 2-microglobulin is a substrate of tissue transglutaminase: polymerization in solution and on the cell surface.
Incubation of purified human beta 2-microglobulin (B2-m) with tissue transglutaminase (Tgase) resulted in the formation of high molecular weight polymers revealed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. In the presence of 30 mM [14C]methylamine, the polymer formation was prevented, but incorporation of methylamine into beta 2-m (equal to 1 methylamine per 1 molecule) could be observed. From the sheddings of peripheral blood mononuclear cells occurring in the presence of Tgase, it is apparent that anti-beta 2-m immunoadsorbent removed, in addition to human leukocyte antigen (HLA) and beta 2-m, some other proteins. The enzyme could incorporate [14C]methylamine into beta 2-m of the shedding cells. On addition of rabbit anti-human beta 2-m antibody, followed by fluoresceine-labeled goat anti-rabbit IgG antibody to human mononuclear blood cells, the otherwise homogeneous distribution of fluorescence turned into spots and patches on cells previously incubated with Tgase or Ca2+-ionophore A23187.
D001609:Beta-Globulins / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism*; D008744:Methylamines / Q000378:metabolism; D011108:Polymers; D001613:beta 2-Microglobulin / Q000276:immunology / Q000378:metabolism*; D005723:gamma-Glutamyltransferase / Q000378:metabolism*
D001609:Beta-Globulins; D008744:Methylamines; D011108:Polymers; D001613:beta 2-Microglobulin; D005723:gamma-Glutamyltransferase