Figure 1. 12% SDS-Page gel of AKR1D1 IPTG induction optimization. SDS-Page was performed on AKR1D1 at various IPTG incubation times and temperatures. The expected length is 37kDa.

Figure 2. GC-MS chromatogram for the optimized derivatization of AKR1D1. The GC-MS chromatogram shows the 0.01% coprostanone standard, which is the hypothesized product of AKR1D1’s conversion from cholestenone, along with the product of a reaction containing AKR1D1, 100µM cholestenone, 500µM NADPH, 100mM potassium phosphate buffer (pH 6.0), 0.2% Triton X-100, and 5% ethanol, incubated for 16 hours at 37 ̊C.

Figure 3. GC-MS chromatogram of three AKR1D1 pop assays in E. coli mixed with cholestenone substrate. The GC-MS chromatogram shows the 0.01% coprostanone standard along with the product of a three AKR1D1 reactions containing, 100µM cholestenone, 500µM NADPH, 100mM potassium phosphate buffer (pH 6.0), 0.2% Triton X-100, and 5% ethanol, incubated for 16 hours at 37°C. AKR1D1 was added to the reaction using the pop assay protocol. The AKR1D1 reaction chromatogram shows a peak directly underneath the coprostanone standard, indicating product formation using the pop assay protocol.