title: Piperazines for peptide carboxyl group derivatization: effect of derivatization reagents and properties of peptides on signal enhancement in matrix-assisted laser desorption/ionization mass spectrometry.
abstract: Piperazine-based derivatives, including 1-(2-pyridyl)piperazine (2-PP), 1-(2-pyrimidyl)piperazine (2-PMP), 1-(4-pyridyl)piperazine (4-PP), and 1-(1-methyl-4-piperidinyl)piperazine (M-PP), were used for the derivatization of carboxyl groups on peptides with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and 1-hydroxy-7-azabenzotriazole (HOAt) as coupling reagents, and trifluoroacetic acid (TFA) as activator. Taking synthetic peptides RVYVHPI (RI-7) and APGDRIYVHPF (AF-11) as samples, the yields of derivatized peptides by 2-PP, 2-PMP and 4-PP were higher than 94%. The effect of piperazine derivatives on the signals of tryptic digests of α-transferrin and bovine serum albumin (BSA) was investigated, and it was found that peptides derivatized by 2-PP and 2-PMP exhibited obviously improved ionization efficiency. Furthermore, comparison of identified peptides before and after derivatization showed that peptides with low molecular weight (MW) and high pI value were preferably detected after derivatization. In addition, after derivatization with 2-PP and 2-PMP, protein myelin basic protein S, 20 kDa protein, and histone H were confidently identified from the tryptic digests of two fractions of rat brain protein separated by reversed-phase high-performance liquid chromatography (HPLC), indicating the potential application of 2-PP and 2-PMP for the highly sensitive determination of peptides in comprehensive proteome analysis.
authors.affiliation: Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic Research & Analysis Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, China.
authors.forename: Xiaoqiang
authors.initials: X
authors.lastname: Qiao
authors.forename: Liangliang
authors.initials: L
authors.lastname: Sun
authors.forename: Lingfan
authors.initials: L
authors.lastname: Chen
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhou
authors.forename: Kaiguang
authors.initials: K
authors.lastname: Yang
authors.forename: Zhen
authors.initials: Z
authors.lastname: Liang
authors.forename: Lihua
authors.initials: L
authors.lastname: Zhang
authors.forename: Yukui
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001923:Brain Chemistry; D002417:Cattle; D030562:Databases, Protein; D008956:Models, Chemical; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism; D010879:Piperazines / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry / Q000378:metabolism; D040901:Proteomics; D051381:Rats; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D014357:Trypsin / Q000378:metabolism
chemical_list: D010455:Peptides; D010879:Piperazines; D011506:Proteins; D014357:Trypsin