I am currently working on a project that aims to measure the protein activity of purified recombinant eNOS. If our protein is active we can continue with binding assays. We attempted to use a fluorometric activity assay to measure the activity but did not have successful results. Prior to assuming this is because our protein may be inactive, I wanted to see if anyone else has had success measuring the activity of this protein specifically from purified protein. Most kits specify using cell or tissue lysate which would not be useful for our goals. If anyone has direction here that would be greatly appreciated. In addition, any tips for working with this protein would be appreciated, as most kits emphasize how unstable the protein tends to be.