ISSN:
1365-3083
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
We report that α-2-macroglobulin (α2M) can form complexes with a high molecular weight porcine mannan-binding protein (pMBP-28). The α2M/pMBP-28 complexes were isolated by PEG-precipitation and affinity chromatography on mannan-Sepharose, protein A-Sepharose and anti-IgM Sepharose. The occurrence of α2M/pMBP-28 complexes was further indicated by crossed immunoelectrophoresis and by use of an anti-α2M affinity column and chelating Sepharose loaded with Zn2+. The eluates from these affinity columns showed α2M subunits (94 and 180 kDa) and pMBP subunits (28 kDa) in SDS-PAGE, which reacted with antibodies against α2M and pMBP-28, respectively, in Western blotting. Furthermore, the α2M/pMBP-28 complexes were demonstrated by electron microscopy, Fractionation of pMBP-containing D-mannose eluate from mannan-Sepharose on Superose 6 showed two protein peaks which reacted with anti-C1 s antibodies in ELISA, one of about 650–800 kDa, which in addition contained pMBP-28 and anti-α2M reactive material, the other with an Mr of 100–150 kDa. The latter peak revealed rhomboid molecules (7 × 15 nm) in the electron microscope and a 67 kDa band in SDS-PAGE under reducing conditions. This band was also seen in eluates from the anti-α2M and chelating Sepharose columns. Based on these observations and previous findings by other investigators of a serine protease with about 67 kDa subunits which copurifies with human MBP we propose a model for the interaction of pMBP-28 with α2M.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-3083.1995.tb03670.x
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