SDS PAGE analysis of α-haemolysin irradiated with 20 μM methylene blue and laser light doses of 1.93 J/cm2, 3.86 J/cm2 and 9.65 J/cm2. α-haemolysin was either kept in the dark (L-) or irradiated with laser light doses of 1.93 J/cm2, 3.86 J/cm2 and 9.65 J/cm2 (L+) in the presence of an equal volume of either PBS (S-) or 20 μM methylene blue (S+) Following irradiation, samples were analysed by SDS PAGE using a 5% stacking gel and 15% resolving gel under denaturing conditions. Lane 1: molecular weight marker, lane 2: L-S-, lane 3: L-S+, lane 4: L+S- (1.93 J/cm2), lane 5: L+S- (3.86 J/cm2), lane 6: L+S- (9.65 J/cm2), lane 7: L+S+ (1.93 J/cm2), lane 8: L+S+ (3.86 J/cm2), lane 9: L+S+ (9.65 J/cm2). L = samples exposed to laser light and S = samples exposed to 20 μM methylene blue. The apparent molecular mass of α-haemolysin was approximately 29 kDa.