title: Quantification of proteins by measuring the sulfur content of their constituent peptides by means of nano HPLC-ICPMS.
abstract: The sulfur (S) concentrations of three peptides were determined by using nano HPLC-ICPMS under a flow of O2 in an octapole reaction cell, and the determined values showed a good agreement with theoretical values. This method was then applied to trypsin-digested peptides from human albumin for protein quantification. Assigning of the number of S atoms in each peptide/peak and the tryptic digestion efficiency were important for protein quantification. The number of S atoms in each peptide/peak was assigned by using verification scores that gave the lowest standard deviation of the peptide S concentration and the highest S recovery. The peptide concentrations were calculated as the ratio of the S concentration/the number of S atoms in the peptide/peak. The tryptic digestion efficiency was calculated as the sum of the S concentration in the mono-peptides divided by the total S concentration in a native polyacrylamide gel electrophoresis (PAGE) band before tryptic digestion. Our result indicates that a protein can be quantified through peptide quantification, after taking into account the tryptic digestion efficiency, via S quantification using ICPMS.
authors.affiliation: Faculty of Science and Engineering, Department of Applied Chemistry, Chuo University.
authors.forename: Yoshinari
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Ayumi
authors.initials: A
authors.lastname: Nobusawa
authors.forename: Naoki
authors.initials: N
authors.lastname: Furuta
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods; D004867:Equipment Design; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods; D010446:Peptide Fragments / Q000737:chemistry*; D011506:Proteins / Q000032:analysis* / Q000737:chemistry; D012015:Reference Standards; D012709:Serum Albumin / Q000032:analysis / Q000737:chemistry; D013455:Sulfur / Q000032:analysis*; D014357:Trypsin / Q000737:chemistry
chemical_list: D010446:Peptide Fragments; D011506:Proteins; D012709:Serum Albumin; D013455:Sulfur; D014357:Trypsin