Fig. 7. Isolation of MAP by isoelectric focussing (IEF) followed by SDS-PAGE with immuno-identification of MAP fractions by western blot using three different antibodies. (A) IEF: Lanes 1-3, water-soluble extract from a whole gonad/mantle. (B) Western blots after IEF revealed with anti-MAP (Lane 4), anti-esterase S (Lane 5), and anti-porcine esterase (Lane 6) antibodies. Note that the same single band of pI 6.2 was detected by all antibodies. (C) SDS-PAGE of MAP fraction (Lanes 1-3) isolated from IEF-gels. Only 39 kDa bands were observed in the SDS-gel, which indicates the homogeneity of the MAP IEF-fraction. (D) Western blots after SDS-PAGE revealed with anti-MAP (Lane 4), anti-esterase S (Lane 5), and anti-porcine esterase (Lane 6) antibodies. The SDS-fraction contains the only 39 kDa mussel MAP, immunologically similar to both D. virilis esterase S and pig esterase.