Bovine Serum Albumin Catalysed Hydrogen and Deuterium Evolution at Mercury Electrodes. Issue 7 (30th July 2020) - Dorčák, Vlastimil
Abstract: The hydrogen evolution reaction (HER), catalysed by proteins at mercury electrodes and reflected in chronopotentiometric stripping peak H, provides a label‐free and reagentless analytical technique that is sensitive to protein structure. Here we show how the kinetic isotope effect affected the HER catalysed by the protein bovine serum albumin (BSA). We found that the deuteron bond, which is stronger than that of a proton, contributed to less effective transport of deuterons mediated by BSA at the Hg|D2 O interface, and enhanced structural stability of the surface‐attached native BSA in D2 O solution. A structural transition was also observed in the surface‐attached urea‐denatured BSA, and is probably due to the destabilisation of some secondary structural remnants retained by the 17 SS‐bonds. Because the catalytically active groups involved in proton or deuteron transfer in native proteins are often exposed towards solutions and their protons exchange almost instantly, no signs of H/D exchange were observed in native BSA using peak H under the given conditions. Abstract : The stronger deuteron bond than that of a proton 1) contributed to less effective transport of deuterons mediated by protein bovine serum albumin (BSA) at the Hg|D2 O interface and 2) enhanced structural stability of the surface‐attached deuteronated native BSA in D2 O solution (BSA−D) where its transition current ( I str1/2 ) was less intense than that of the protonated BSA in H2 O solution (BSA−H).