Premium
Hydrogen/deuterium exchange kinetics of cytochrome C : An electrospray ionization fast flow experiment
Author(s) -
Geller Orit,
Lifshitz Chava
Publication year - 2004
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1560/6vb6-rrdt-qm9x-3qaa
Subject(s) - chemistry , deuterium , hydrogen–deuterium exchange , protonation , electrospray ionization , reaction rate constant , kinetics , hydrogen , analytical chemistry (journal) , ion , ionization , atomic physics , chromatography , organic chemistry , physics , quantum mechanics
New experiments are described in which the gas phase hydrogen/deuterium (H/D) exchange kinetics is studied for multiply‐protonated cytochrome c ions with +10 to +17 charges. The experimental technique involves electrospray ionization (ESI) combined with a fast‐flow method. Experimental results are presented including (1) average rate constants for H/D exchange, (2) overall decay kinetics of the reactant ion, and (3) sets of profiles for consecutive deuterium exchanges as a function of the flow rate of ND 3 as the deuterating agent. The maximum number of exchanged hydrogen atoms and the exchange rate are observed to increase with increasing charge. The +13 state demonstrates special reactivity with a reactant ion decay constant of 2.5 × 10 −9 cc/molecule's. Further insight into the H/D exchange mechanism is anticipated upon analysis of the data with a newly developed algorithm for extracting site‐specific rate constants from profiles for H/D exchange in gas phase protonated amino acids, their clusters, and peptides. The algorithm minimizes the mutual entropy or the Kullback‐Leibler information divergence between the observed concentrations and a chosen model.