Guanine nucleotide product blog Tags: Nucleotide; Guanine; Guanine nucleotide; Posted by mybiosource_staff on . The Guanine n/a (Catalog #MBS657834) is a Nucleotide and is intended for research purposes only. The product is available for immediate purchase.To buy or view more detailed product information and pricing, please click on the technical datasheet page below:GuanineCAS Number: 73-40-5Molecular Formula: C5H5N5O. Melting Point: >300 degree C.