Analysis of protein digests by transmission-mode desorption electrospray ionization mass spectrometry with ultraviolet photodissociation

Transmission mode desorption electrospray ionization is coupled with ultraviolet photodissociation at 193 nm for the analysis of protein digests. SEQUEST is utilized for data interpretation and database searches. Comparative results are presented for transmission mode desorption electrospray ionization (TM-DESI)-MS/collision induced dissociation (CID) and TM-DESI-MS/ultraviolet photodissociation (UVPD) analyses of five proteolyzed model proteins ranging in molecular weight from 8.5 kDa (ubiquitin) to 66 kDa (bovine serum albumin, BSA). In some cases TM-DESI/UVPD yielded greater confidence in database correlation scores for peptides and comparable protein identification compared to TM-DESI-MS/CID due to the production of an extensive array of sequence ions and the ability to detect low m/z terminal sequence ions and immonium ions. (C) 2011 Elsevier B.V. All rights reserved.