Reduced von Willebrand Factor Fragment in Plasma

Zimmerman et al reported that normal plasma vWF contains proteolytic fragments of 225, 189, 176, and 140 kDa with anti-vWF monoclonal antibodies in the presence of protease inhibitors and partial cleavage of the plasma vWF subunit is a normal event. Now we report here the analysis of normal plasma vWF with home-made polyclonal anti-reduced vWF antibody by using a small amount of normal plasma itself. With this reference, the vWF fragments with mobility corresponding to 240, 216 (220, 210), 194, 164, and 144 kDa were detected. Also by means of employing anti-reduced SP III and SP II antibody, we suggested that the 164 kDa fragment is located close to the carboxy terminal and the 194 and 144 kDa fragments are located close to the amino terminal. Furthermore, the vWF fragments showed no difference in mobility with or without protease inhibitor. In vivo proteolytic degradation of vWF occurring normally was also shown by our technique.