Treatment of pediatric acute lymphoblastic leukemia (ALL) with pegaspargase exploits ALL cells dependency on asparagine. Pegaspargase depletes asparagine, consequentially affecting aspartate, glutamine and glutamate. The gut as a confounding source of these amino acids (AAs) and the role of gut microbiome metabolism of AAs has not been examined. Understanding how microbial gene-products, which interact with these AAs change over treatment were examined. Understanding pathways that change AA availability, including by microbes in the gut, could be useful in optimizing pegaspargase therapy.