Photolytic labeling to probe molecular interactions in lyophilized powders.

ABSTRACT: Local side-chain interactions in lyophilized protein formulations were mapped using solid-state photolytic labeling-mass spectrometry (ssPL-MS). Photoactive amino acid analogues (PAAs) were used as probes and either added to the lyophilized matrix or incorporated within the amino acid sequence of a peptide. In the first approach, apomyoglobin was lyophilized with sucrose and varying concentrations of photoleucine (L-2-amino-4,4'-azipentanoic acid; pLeu). The lyophilized solid was irradiated at 365 nm to initiate photolabeling. The rate and extent of labeling were measured using electrospray ionization/high-performance liquid chromatography/mass spectrometry (ESI-HPLC-MS), with labeling reaching a plateau at ~30 min, forming up to six labeled populations. Bottom-up MS/MS analysis was able t

SUBMITTER: Iyer LK 

PROVIDER: S-EPMC3913734 | biostudies-literature | 2013 Dec

REPOSITORIES: biostudies-literature