An infrared investigation of palmitoyl-coenzyme A and palmitoylcarnitine interaction with perdeuterated-chain phospholipid bilayers.
Mixtures of di-(perdeuteropalmitoyl)-sn-glycero-3 choline ([2H62]Pam2GroPCho) with palmitoylcarnitine or palmitoyl-CoA in aqueous suspension have been examined by Fourier-transform infrared spectroscopy. The C-H (or C-D) region of the spectrum shows that an order-disorder transition exists in pure aqueous palmitoylcarnitine at 45 degrees C; palmitoylcarnitine mixes with [2H62]Pam2GroPCho without perturbing the gel-fluid transition of the phospholipid even at [2H62]Pam2GroPCho/palmitoylcarnitine 1:2 molar ratios; and palmitoyl-CoA, however, at similar proportions, smears out the [2H62]Pam2GroPCho transition as detected from C-D stretching vibrations. Relevant data from the carbonyl region include; the high-frequency (non-hydrogen bound) carbonyl subpopulation, but not the low frequency one, detects the gel-to-fluid transition of the phospholipid; the carbonyl region detects the thermotropic transition over a wider temperature range than the methylene stretching region, i.e. detects changes starting well below and ending several degrees above the methylene transition temperature, and a significant interaction may occur between some coenzyme A group and the carbonyl groups of the phospholipid. The latter interaction may contribute to explain the coenzyme A/carnitine exchange during mitochondrial fatty acid import.
Echabe
I
I
Department of Biochemistry, University of the Basque Country, Bilbao, Spain.
Requero
M A
MA
Goñi
F M
FM
Arrondo
J L
JL
Alonso
A
A
D003903:Deuterium / Q000737:chemistry*; D008051:Lipid Bilayers; D010171:Palmitoyl Coenzyme A / Q000737:chemistry*; D010172:Palmitoylcarnitine / Q000737:chemistry*; D010743:Phospholipids / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature
D008051:Lipid Bilayers; D010743:Phospholipids; D010171:Palmitoyl Coenzyme A; D010172:Palmitoylcarnitine; D003903:Deuterium