Purity >90% by SDS-PAGE. StayBrite Highly Stable Luciferase (rLucHS) is a genetically modified variant derived from the Luciferase of Diaphanes pectinealis (Chinese Firefly) endemic to Yunnan province, China. It has been modified to provide enhanced stability compared to the normal phenotype of Photinus pyralis as well as a broader and more physiologically relevant effective pH range. At all pHs below 8.2, rLucHS is significantly more active than commercial Photinus luciferase and is stable for weeks at room temperature and > 60 minutes at 37°C.