title: Correlation between phosphorylation ratios by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis and radioactivities by radioactive assay.
abstract: To investigate the correlation between the counts per minute (CPM) by radioactivity assay and the phosphorylation ratio by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis, we prepared 136 peptide substrates. The correlation coefficient of phosphorylation ratios to CPM was 0.77 for all samples. However, the more the numbers of positively charged amino acids increased, the more the correlation coefficient increased. Although positively charged amino acids can have an effect on the correlation results, MALDI-TOF MS analysis is a useful means for monitoring phosphorylated peptide and protein kinase activity instead of radioactivity assays.
authors.affiliation: Graduate School of Systems Life Sciences, Kyushu University, Nishi-Ku, Fukuoka 819-0395, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Tsuchiya
authors.forename: Daisuke
authors.initials: D
authors.lastname: Asai
authors.forename: Jeong-Hun
authors.initials: JH
authors.lastname: Kang
authors.forename: Takeshi
authors.initials: T
authors.lastname: Mori
authors.forename: Takuro
authors.initials: T
authors.lastname: Niidome
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Katayama
mesh_terms: D010455:Peptides / Q000737:chemistry*; D010766:Phosphorylation; D011851:Radioactivity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D010455:Peptides