Isolation and characterization of two different molecular forms of basic fibroblast growth factor extracted from human placental tissue

Abstract

Basic fibroblast growth factor (bFGF) was purified to homogeneity from human placental tissue on a semi-large scale. Placental bFGF consists of two proteins of apparent molecular masses 16 000 and 18 000 dalton, as determined by sodium dodecyl sulphate polyaerylamide gel electrophoresis under non-reducing conditions. Microsequence analysis showed that both proteins have ilic same N-terminal sequence Pro—Ala—Leu—Pro—Glu—Asp—Gly—Gly—Ser—Gly—Ala—Phe..., which is identical with that of (1—146) bFGF extracted from human brain. After reduction by dithiothreitol or mereaptoethanol, placental bFGF appears as a single protein of 16 000 dalton. The reduced protein displays the same ability to stimulate the proliferation of CCL39 fibroblasts as the non-reduced doublet. These data indicate that bFGF extracted from placental tissue consists of two proteins with different apparent molecular masses which do not differ in their N-terminal sequence but in their oxidation state.