title: Complexes of cadmium ion with guanine bases detected by electrospray ionization mass spectrometry.
abstract: The complexations of cadmium ion with guanine bases were detected by electrospray ionization mass spectrometry (ESI-MS). In order to explore the toxicity of cadmium, such as oxidative stress to DNA and carcinogenesis, it is very important to determine the interactions between the cadmium ion and nucleotide. The analysis of mixed cadmium ion-guanosine aqueous solution (molar ratio 1 : 9) using ESI-MS (cone voltage 20 V) showed the presence of various cadmium complex ions, such as [n (guanosine) + Cd](2+) (n = 3-8), [2guanine + Cd](2+), [guanosine + guanine + Cd](2+) and [guanosine + 2guanine + Cd](2+). The observed [2guanine + Cd](2+), [guanosine + guanine + Cd](2+) and [guanosine + guanine + Cd](2+) ions are formed through the dissociation of the N-glycoside bond at the interface of ESI-MS. For deoxyguanosine and ethylguanine, similar cadmium complexes were observed. However, the complexes between the cadmium ion and 8-hydroxydeoxyguanosine were not detected. Furthermore, when a higher molar ratio (Cd : guanosine) or cone voltage were used, more of the monovalent ion peaks, such as [Cd(guanine - H)(2) + H](+) and [Cd(guanosine - H)(2) + H](+), were observed and a decrease in the abundance of the divalent ions, such as [n(guanosine)+Cd](2+), occurred.
authors.affiliation: Osaka City Institute of Public Health and Environmental Sciences, 8-34, Tojo-cho, Tennoji-ku, Osaka 543-0026, Japan. Hiroshi.Moriwaki@iphes.city.osaka.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Moriwaki
mesh_terms: D002104:Cadmium / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D006147:Guanine / Q000737:chemistry / Q000378:metabolism*; D015394:Molecular Structure; D009711:Nucleotides / Q000737:chemistry / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D009711:Nucleotides; D002104:Cadmium; D006147:Guanine