Spontaneous aggregation of low molecular weight factor VIII and its prevention by 2mM CaCl 2

Abstract

Low molecular weight factor VIII was prepared by chromatography of a commercial factor VIII concentrate on Bio-Gel A-15m with buffer containing 0.25 M CaCl 2. When the low molecular weight material was rechromatographed in imidazole buffered normal saline, the procoagulant activity appeared in the void volume. If 0.002 M CaCl 2 was added to the elution buffer, the recovered activity was again eluted with proteins of low molecular weight. These experiments demonstrate that dissociated low molecular weight factor VIII can undergo spontaneous aggregation which can be prevented by physiologic levels of CaCl 2.