This cluster of papers focuses on the intricate regulation and metabolic pathways of nucleotide biosynthesis, including purine and pyrimidine biosynthesis. It explores the structure, function, and inhibition of key enzymes such as CTP synthase, IMP dehydrogenase, and dihydroorotate dehydrogenase. The cluster also delves into disorders related to nucleotide metabolism, such as Lesch-Nyhan syndrome.