IMMUNOLOGICAL IDENTITY OF RAT-LIVER CYTOSOLIC HEME-BINDING PROTEIN WITH PURIFIED AND RECOMBINANT LIVER FATTY-ACID-BINDING PROTEIN BY WESTERN BLOTS OF 2-DIMENSIONAL GELS

We examined the degree of similarity between rat liver cytosolic heme- binding protein (HBP) and rat liver fatty acid binding protein (L-FABP ) purified from rat liver cytosol and recombinant L-FABP (rL-FABP). We compared 1) HBP, 2) L-FABP, and 3) rL-FABP prepared in three differen t laboratories and probed them with three different antisera also from different laboratories on Western blots. The objective was to determi ne whether the isoform pattern of the recombinant would resemble those of the purified rat liver proteins and whether heme is bound by the i soforms. To investigate the similarities, we compared the immunoreacti vity of purified HBP, L-FABP, and rL-FABP by probing Western blots of 2-D gels with polyclonal antibodies raised against each of these prote ins. Ah of the antibodies react with the same isoelectric species for each of the proteins. Ln addition, [Fe-55]-heme binds equally well to the 2 major HBP isoforms. (C) 1994 Academic Press, Inc.