Cycloheximide ≥90 %, for biochemistry Antibiotic isolated from Streptomyces griseus . Its main biological activity is translation inhibition in eukaryotes by binding to the 60S subunit of the ribosomes. Cycloheximide inhibits binding of Aminoacyl-tRNA to the ribosomes, Peptidyltransferase, detachment of deacylated tRNA, and translocation of Aminoacyl-tRNA, resulting in cell growth arrest and apoptotic cell death. Not effective against bacteria. Cycloheximide is widely used for selection of cycloheximide-resistant strains of yeast and fungi, for inhibition of eukaryotic contaminants in bacterial microbiology, for controlled inhibition of protein synthesis in cell culture and for detection of short-lived proteins, and for apoptosis induction or facilitation of apoptosis induction by death receptors.