Spectinomycin dihydrochloride pentahydrate is an aminocyclitol antibiotic which is closely related to the aminoglycosides, produced by a species of soil microorganism Streptomyces spectabilis. It has a broad spectrum of activity against many Gram-positive and Gram-negative bacteria. It exerts bactericidal effect by inhibiting protein synthesis at prokaryotic ribosomal level. It binds to 30S ribosomal subunit and interferes with the translocation of peptidyl tRNA, thereby inhibiting protein synthesis. In cell culture, it is used as an anti-bacterial agent to prevent contamination. Spectinomycin is used as a selection agent for resistant bacteria and plant cells. Directions : For cell culture applications, spectinomycin is used at concentration of 7.5 to 20mg/L. Preparation instructions: Spectinomycin dihydrochloride pentahydrate is soluble in water (50mg/ml). Spectinomycin solutions are sterilized by filtering through a sterile membrane filter with a porosity of 0.22micron or less.