Retinylidene Schiff bases in alkylammonium carboxylate reversed micelles.
All-trans-retinal, incorporated into dodecylammonium propionate, dodecylammonium 3-chloropropionate and dodecylammonium trifluoroacetate reversed micelles in cyclohexane containing different amounts of solubilized water, gave all-trans-N-retinylidene-n-dodecylamine. Formation of all-trans-N-retinylidene-n-dodecylamine was complete within a few minutes when all-trans-retinal was solubilized along with L-lysine in reversed-micellar dodecylammonium propionate in cyclohexane as compared to the several hours required for the comparable reaction to occur in the absence of lysine. In situ formed all-trans-N-retinylidene-n-dodecylamine was not protonated by the acidic moiety (i.e., propionate, 3-chloropropionate or trifluoroacetate anions) of dodecylammonium propionate, dodecylammonium 3-chloropropionate or dodecylammonium trifluoroacetate reversed micelles. Addition of propionic or 3-chloropropionic acid did not cause observable protonation of the reversed-micelle-incorporated all-trans-N-retinylidene-n-dedecylamine. Addition of strong trifluoroacetic acid to reversed micellar solutions of all-trans-N-retinylidene-n-dodecylamine caused protonation as well as hydrolysis to retinal. Retinylidene Schiff bases are protected from protonation by strongly held surfactant-ion pairs which may model proton channels whose function is controlled by protein conformational changes.
Singh
A K
AK
Département de Chimie, Université de Montréal, Canada.
Sandorfy
C
C
Fendler
J H
JH
D003510:Cyclohexanes; D053138:Cyclohexenes; D008823:Micelles; D011522:Protons; D012172:Retinaldehyde / Q000737:chemistry*; D012243:Rhodopsin / Q000737:chemistry*; D012545:Schiff Bases
D003510:Cyclohexanes; D053138:Cyclohexenes; D008823:Micelles; D011522:Protons; D012545:Schiff Bases; C052568:cyclohexene; D012243:Rhodopsin; D012172:Retinaldehyde