Complex sentence: It was originally hypothesized that Salinosporamide B was a biosynthetic precursor to Salinosporamide A due to their structural similarities with the halogenation of the unactivated methyl group being catalyzed by a non-heme iron halogenase.
Split into simpler sentences: It was originally hypothesized that Salinosporamide B was a biosynthetic precursor to Salinosporamide A due to their structural similarities. The halogenation of the unactivated methyl group being catalyzed by a non-heme iron halogenase.