Effect of iodination on the pK of Schiff base deprotonation and M412 production in purple membrane

G. Gogel*, Aaron Lewis

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

Previously, kinetic resonance Raman measurements as a function of pH have been used to demonstrate that, microseconds after light absorption, the pK of Schiff base deprotonation during the bacteriorhodopsin photocycle is 10.2 ± 0.3, whereas before the light event, the pK is > 12 (2). In this investigation, we have iodinated purple membrane suspensions and have found that the pK of Schiff base deprotonation in the photocycle has been lowered to between 7 and 8 for iodinated bacteriorhodopsin. These results, together with our previous data on the pK of Schiff base deprotonation, suggest that the amino acid tyrosine could be a critical component in the deprotonation mechanism.

Original languageEnglish
Pages (from-to)175-181
Number of pages7
JournalBiochemical and Biophysical Research Communications
Volume103
Issue number1
DOIs
StatePublished - 16 Nov 1981
Externally publishedYes

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