Fig. 4.

Chemical chaperones effect on wild-type and I278T CBS protein. (a) Yeast expressing either wild-type or I278T CBS were grown in SC + cys media with the indicated chemical chaperone overnight, and total lysates were examined for CBS by both native and denaturing PAGE followed by immunoblot as described in ‘Materials and methods’. Extracts were also examined for CBS activity as described in ‘Materials and methods’. D indicates 0.64 M DMSO. G is 0.44 M glycerol. Set 3 contains 0.4 M sorbitol, 0.44 M glycerol, and 128 mM DMSO. Activity is expressed in nmoles/mg total protein per hour. (b) Yeast expressing the indicated allele of CBS were grown in SC + cys media either in the presence (+) or in the absence of 1 M TMAO overnight. Total cell lysates were prepared and examined for CBS by both native and denaturing PAGE followed by immunoblot as described in ‘Materials and methods’. CBS enzyme activity was also determined for each lysate and results are expressed in nmoles/mg total protein per hour.