NATURAL HEPATOCYTE GROWTH-FACTOR (HGF) FROM HUMAN SERUM AND A BOUND FORM OF RECOMBINANT HGF WITH HEPARAN-SULFATE ARE INDISTINGUISHABLE IN THEIR PHYSICOCHEMICAL PROPERTIES

Natural hepatocyte growth factor (nHGF) purified from human serum show ed a difference in molecular mass (M-r) between SDS-PAGE (76-90 kDa) a nd gel filtration chromatography on a Sephadex G-200 column (> 200 kDa ), whereas nHGF or recombinant HGF (rHGF) from cell culture medium did almost the same M-r (74-100 kDa). A bound form of rHGF with heparan s ulfate (or heparin), and an aggregate form of rHGF itself showed a hom ogeneous band with a M-r of 76-90 kDa on SDS-PAGE, but showed a M-r la rger than 200 kDa on a Sephadex G-200 column. Both nHGFs, rHGF and the bound form were basic, but the aggregate form was acidic in ionic nat ure. No significant difference was found in affinity for heparin among these HGF preparations. The bound form treated by the procedures for purification of nHGF from human serum still showed a larger molecular form. The bound form mimicked physicochemical properties of nHGF purif ied from human serum. These results suggest that a possible form of nH GF in human serum may be a bound form with heparin-like molecules such as heparan sulfate, which are found in the circulation and on cell su rface, and purified as the bound form. (C) 1998 Elsevier Science B.V. All rights reserved.