Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1937614 | Biochemical and Biophysical Research Communications | 2007 | 6 Pages |
Abstract
α2-Macroglobulin (α2M) is a proteinase inhibitor that functions by a trapping mechanism which has been exploited such that the receptor-recognized, activated form (α2Mâ) can be employed to target antigens to antigen-presenting cells. Another potential use of α2Mâ is as a drug delivery system. In this study we demonstrate that guanosine triphosphate, labeled with Texas red (GTP-TR) formed complexes with α2Mâ following activation by proteolytic or non-proteolytic reactions. Optimal incorporation occurred with 20 μM GTP-TR, pH 8.0 for 5 h at 50 °C. NaCl concentration (100 or 200 mM) had little effect on incorporation at this pH or temperature, but was significant at sub-optimum temperature and pH values. Maximum incorporation was 1.2 mol GTP-TR/mol α2Mâ. PAGE showed that 70-90% of the GTP-TR is bound in a SDS/2-mercaptoethanol resistant manner. Guanosine, adenosine, and imidazole competed with GTP-TR to form complexes with α2Mâ.
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Authors
Jennifer E. Bond, George J. Cianciolo, Salvatore V. Pizzo,