5. DISTRIBUTION OF PHOSPHOLIPIDS
245
presence of phosphatidylcholine and phosphatidylethanolamine is well
established. Sphingomyelin, if present, occurs in trace amounts only.
No evidence for phosphatidylserine was found in these two species,
TABLE V
THE PHOSPHOLIPID CONTENT OF SKELETAL, CARDIAC, AND SMOOTH MUSCLE
0
Species
Systematic name
Class Mammalia
Homo sapiens
Canis familiaris
Felis domestica
Lepus sp.
Sylvilagus floridanus
Macropus ruf us
Class Aves
Gallus gallus
Columbidae family
Passer domestica
Scops asio
Class Amphibia
Rana pipiens
Class Reptilia
Pseudemys scripta elegans
Alligator
mississippiensis
a Adapted from Bloor {50).
d Intestine.
Common name
Man
Dog
Cat
Hare
Wild rabbit
Red kangaroo
Hen
Pigeon
House sparrow
Screech owl
Leopard frog
Scribe turtle
Alligator
Phospholipid
(% of dry weight)
Skeletal
6
—
8.0
2.5
1.7
3.7
2.4
3.7
4.5
4.4
3.6
3.8
3.5
2.0
b Thigh.
c Uterus.
e Stomach.
f Gizzard.
Cardiac
7.0
8.5
5.7
9.1
7.6
6.7
7.6
7.3
8.5
6.2
4.2
6.4
7.5
Smooth
3.5
C
3.0
C
3.2
d
4.4
C
2.5*
—
2.0/
2.5/
2.8/
3.5/
—
—
—
but both serine and threonine have been reported in the phospholipids
of tunny muscle (64). Plasmalogens are present but apparently in much
RO
II
-cHX-O
I
o-cH 2 CH
O
II
-co
R
H 2 C
O
II
O—P—O—CH 2
"I
I
\
H—C—OH OH
H—CO
II
-cO—P-O—CH 2
I
o
II
OH
R—C—O—CH 2
FIG. 5. The structure of beef heart cardiolipin.
dence for three different inositides has been obtained and also for two
different polyglycerophosphatides. Apparently neither of these last two
have the structure of beef heart cardiolipin, as fatty acid, glycerol, and
phosphorus were found in a ratio of 4: 2:1.