Protease digestion of the purified major allele MBP-CBS fusion protein. Protease digestion of the purified major allele MBP-CBS fusion protein. After treatment with thermolysin for the indicated time (minutes), the digested protein is separated by polyacrylamide gel electrophoresis. The full-length CBS protein (with MBP removed) runs as a doublet; the identities of all of the labeled bands were confirmed by Mass-Spectrometry analysis. Iota marks the lane with no protease. Dago Dimster-Denk et al. G3 2013;3:1619-1628 ©2013 by Genetics Society of America