Pyrroline-5-carboxylate reductase (P5CR) is an important housekeeping protein widely found in
prokaryotes and eukaryotes. In the presence of NAD(P)H, pyrroline-5-carboxylic acid (P5C) is converted
to proline by pyrroline-5-carboxylate reductase, and P5CR has also been found to be involved in the
metabolism of thioproline in E. coli.
Thioproline is dehydrogenated by pyrroline-5-carboxylate reductase and is accompanied by the
conversion of NAD to NADH. In the presence of 1-mPMS, WST-1 reacts with NADH to produce water-
soluble formazan with a characteristic absorption peak at 450 nm.
Reagents and Equipment Required but Not Provided:
Spectrophotometer, water bath/constant incubator, adjustable pipette, analytical balance,
mortar/homogenizer/cell sonicator , 1mL glass cuvette, distilled water and ice.