1.3.98.4 7,8-didemethyl-8-hydroxy-5-deazariboflavin i.e. cosynthetic facor-1 738442 1.3.98.4 additional information cosynthetic factor-1 enables Streptomyces aureofaciens to produce tetracycline instead of their 5a,11a-dehydro analogues 738462 1.3.98.4 additional information isolation of Cosynthetic Factor I, required for catayltic activity. The factor is dialysable and stable to autoclaving over the pH range of 1 to 10 738462