Fig. 1. (A) The ink of Aplysia californica containing escapin, a 60 kDa protein. (B) SDS-PAGE of raw purple ink (left lane) and ink purified as described in the Materials and methods to yield escapin, a 60 kDa protein (right lane). Molecular mass standards are also shown. (C) Analytical gel filtration shows that escapin elutes as a single peak. Absorbance is expressed on a relative scale; mAu, milliabsorbance units. Arrow and arrowhead indicate elution times for escapin and BSA, respectively. The inset shows elution volumes of molecular mass standards: BSA, 67 kDa; ovalbumen, 43 kDa; chymotrypsinogen A, 25 kDa, demonstrating that native (non-denatured) escapin has molecular mass of ca. 60 kDa, similar to that of the denatured escapin, as shown in B. The photograph in A is courtesy of Genevieve Anderson.