title: Electrospray ionization quadrupole time-of-flight mass spectrometry and quadrupole mass spectrometry for genotyping single nucleotide substitutions in intact polymerase chain reaction products in K-ras and p53.
abstract: Single nucleotide polymorphisms (SNPs) and mutations were genotyped for both homozygous and heterozygous PCR products of p53, a tumor suppressor gene, and K-ras, an oncogene, using electrospray ionization (ESI) quadrupole time-of-flight (Q-TOF) mass spectrometry (MS) and ESI-quadrupole MS analysis. Mass accuracy was adequate for both instruments to detect genetic changes in homozygous PCR products, including the most difficult to distinguish (adenine [A] --> thymine [T] transversion). However, for the detection of A --> T shifts (9.0 Da difference) in heterozygous PCR products, the increased resolution of ESI-Q-TOFMS proved essential. Although, greater mass differences in heterozygotes (e.g. cytosine [C] <--> T or guanine [G] <--> A) can be discriminated using ESI-quadrupole MS analysis.
authors.affiliation: Department of Pathology and Microbiology, University of South Carolina, School of Medicine, Columbia, SC 29208, USA.
authors.forename: Warees T
authors.initials: WT
authors.lastname: Muhammad
authors.forename: Karen F
authors.initials: KF
authors.lastname: Fox
authors.forename: Alvin
authors.initials: A
authors.lastname: Fox
authors.forename: William
authors.initials: W
authors.lastname: Cotham
authors.forename: Michael
authors.initials: M
authors.lastname: Walla
mesh_terms: D001483:Base Sequence; D016158:Genes, p53 / Q000235:genetics*; D011905:Genes, ras / Q000235:genetics*; D005838:Genotype; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D008969:Molecular Sequence Data; D017354:Point Mutation / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods*; D017422:Sequence Analysis, DNA; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*