SEM observation of elastin degradation by pseudoalterin. Pseudoalterin was added to bovine elastin at a ratio of 1:500 in 50 mm Tris-HCl (pH 9.0) at 25 °C with continuous stirring for 20 min (B), 40 min (C), 60 min (D), and 80 min (E and F). The same reaction system without pseudoalterin served as control (A). After washing twice with deionized water, the insoluble material was lyophilized and mounted on stubs, spatter-coated with 5 nm platinum, and examined with a Hitachi FE-S4800 at 5.0 kV. Bars, 1 μm.