TY - JOUR
T1 - Effect of iodination on the pK of Schiff base deprotonation and M412 production in purple membrane
AU - Gogel, G.
AU - Lewis, Aaron
PY - 1981/11/16
Y1 - 1981/11/16
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=0019882985&partnerID=8YFLogxK
U2 - 10.1016/0006-291X(81)91676-4
DO - 10.1016/0006-291X(81)91676-4
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C2 - 7317062
AN - SCOPUS:0019882985
SN - 0006-291X
VL - 103
SP - 175
EP - 181
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 1
ER -