The D96N mutant form of bacteriorhodopsin (bR) purple membrane fragmen
ts isolated from Halobacterium salinarium has been entrapped in sol-ge
l glass and dried. The photo-activity of the bR was monitored during d
rying over a period of 60 days. The entrapped bR was initially dried a
t 4 degrees C followed by room temperature storage. Samples showing co
nstant activity after storage at 4 degrees C lost further activity at
room temperature, eventually reaching a level where the activity remai
ned constant. Upon further drying at 100 degrees C in a vacuum oven th
e glass lost an additional 11.4 +/- 1.3% weight and all remaining acti
vity.