- One of the four bases in DNA that make up the letters ATGC. Guanine is the "G". The others are adenine, cytosine, and thymine. Guanine always pairs with cytosine to form the base pair G-C (guanine-cytosine) in the DNA. The other base pair in the DNA is A-T (adenine-thymine). Each base pair forms a rung in the DNA ladder. Guanine is also one of the four bases in RNA.
* * *2-Amino-6-oxypurine; one of the two major purines (the other being adenine) occurring in all nucleic acid s.- g. aminase SYN: g. deaminase.- g. deaminase a deaminase of the liver that catalyzes the hydrolysis of g. into xanthine and ammonia; the first step in purine degradation. SYN: guanase, g. aminase.
* * *gua·nine 'gwän-.ēn n a purine base C5H5N5O that codes genetic information in the polynucleotide chain of DNA or RNA compare ADENINE, CYTOSINE, THYMINE, URACIL
* * *n.
* * *gua·nine (gwahґnēn) a purine base, in animal and plant cells usually occurring condensed with ribose or deoxyribose to form the nucleosides guanosine and deoxyguanosine; these nucleosides are components of nucleic acids and of free nucleotides important in metabolism. Symbol G. See also illustration of purine and pyrimidine bases, under base.
Medical dictionary. 2011.