1-01, so
G . V. MARINETTI,J. ERBLAND AND E. STOTZ
162-1 [CONTRIDUTION
FROM TIIE
DEPARTMENT
OF
BIOCHEMISTRY, UNIVERSITY DENTISTRY]
OF
ROCHESTER SCHOOL
OD
MEUICINE
AXD
The Structure of Pig Heart Plasmalogens BY
G.T'. L f A R I N E T T I , J. ERBLAND A N D E. STOTZ RECEIVED SEPTEMBER 23, 1957
A long chain glycerol ether has been isolated by prolonged acid hydrolysis of reduced total pig heart phosphatides, pig heart lecithin arid pig heart cephalin. In all cases the glycerol ethers react with one mole of periodic acid per mole of conipound and therefore must be a-ethers. The iiifrared spectra and paper chromatographic mobility of the isolated glycerol ethers are identical t o those of a n authentic synthetic sample of d-a-octadecyl glycerol ether. Elementary analysis is d1-0 in agreement with this latter structure. The pig heart lecithin was purified by column chromatography and shown to be LL mixture of the diester lecithin (60%) and the monoester-acetal type lecithin (40%). This was demonstrated by chemical analysis and by mild acid hydrolysis. The latter treatment converted 40% of the total lecithin to lysolecithin with the concomitant liberation of a long chain aldehyde. These findings demonstrate t h a t some of the plasmalogens of pig heart muscle contain the long chain aldehyde on the a-carbon atom of the glycerol moiety and the long chain fatty acid on the @-carbon atom of this alcohol.
Plasmalogens were first isolated in 1939 by Feulgen and Bersin.' Later, Thannhauser and collaborators* obtained a similar compound from brain. The cyclic acetal structure (a) first proposed for these plasmalogens has now been shown to be difOH
I CH-O-CH-CH,-R
C€I,-O,
I
CH-0
I
,CH-CHg-R /
CHn----O-Ph-base a
I
0
I I1 CH-0-C-R' I
CH2-0-Ph-base b
CH,-0-CH=CH--R 0
R , R ' = hydrocarbon chain
CH-0-C-Itural product of the type which was used. The infrared spectra of the recrystallized glycerol ether IX and the synthetic octadecyl glycerol ether were run in KBr a t a concentration of 0.6 mg. per gram of I(Br.Ia The spectra of these two compounds were identical. The major spectral bands (in microns) were: 2.94, 3.43, 3.51, 6.82, 7.25, 7.53, 8.05, 8.94, 9.44, 10.70, 10.94, 11.6, 13.92. I. Paper Chromatographic Analysis of the Glycerol Ether IX and the Purified Phosphate Derivative VII1.-Conipounds VIII, IX and the synthetic octadecyl glycerol ether were arialyzed by paper chronintography in two solvent systems. The first consisted of n-heptane-diisobutyl ketone 70: 60 and employed silicic acid impregnated paper which was prepared as described previously.'O Compound I S and the synthetic glycerol ether had the sanie Rr value ( K r 0.22). The glycerol ether phosphate VI11 had an Rfvalue of 0.00 in this system. The second system consisted of acetic acid-water 90: 10 (saturated with liquid petrolatum) and employed filter paper impregnated with a l0yosolution of liquid p e t r o l a t u ~ n . ~Both ~ the natural glycerol ether IX and the synthetic octadecyl glycerol ether had the same Rr value (Rf0.81). The Rfvalue of the glycerol phosphate ether VI11 in this latter system was 0.52. The compounds were detected on chromatograms with Rhodamine 6G (0.001";, aqueous solution) as described previously.'" The natural glycerol ether I X and the synthetic glycerol ether appeared as yellow spots under ultraviolet light (on wet chromatograms) whereas the phosphate coinpound VI11 appeared blue. J. Periodate Oxidation of the Glycerol Ether 1X.-The glycerol ether IX was dissolved in chloroform at a conceiitration of 1.87 mg. per 2.0 ml. Two-nil. aliqunts containing 5.45 p M of conipound (based on a nlolecular ivt. of 344) were pipetted into test-tubes and evaporated to dryness. T o each tube was added 4.0 nil. of 95':; ethanol. After the compound had dissolved, 0.1 inl. of 0.1 dl phosphate buffer pH 7.4 was added. T o one tube which served as the control was added 1.0 ml. of water and to the other tube was added 1.0 ml. of 0.01 Af N a I 0 4 . The optical density of the solutions was determined a t 300 m p a t 15-min. intervals for a period of 5 hours. The reaction was esyentially coniplete by this time. The periodate consumption v s . time (16) E. Baer a n d 0 . I.. Pischer. J . B i o l . C ' h e m . , 140, 397 (1941). (17) Analysis was done by t h e Schnarzkopf Rficroanalytical I.ab., Woodside, S . IT. (18) T h e infrarrd spectra were run b y D r . XY.I3 hfason and h l r . A . Rehringer of t h e I J n i v . of Rochester Atomic Energy Project and were made p u s i b l e i n p a r t by fiinds from t h e I;, S Atumic Energy Commission. A Perkin-Elmer modrl 21 I)ouble n r n m Spectro1,h~itonleter (rock salt prism) was used. 56, 154 (19) H 1'. Rniifrnnnn nn11 TV. TI. Nitwll, P i a / / r nwil ,T
