166
JAMES K. GRANT
OH
CH 3
I
I
CoASCO-CH 2 -C-CH 2 -COSCoA
► HOCH 2 -CH 2 -C-CH 2 -COOH
I
I
CH 3
OH
β -Methyl- ß -hy droxyglutary 1-Co A
(IV)
Mevalonic acid
(V)
CHXOSCoA
OH
I
HOOC-CH 2 -C-CH 2 -CH 2 OP0 2 H
I
I
CH 3
0
P0 3 H 2
Mevalonic acid
5-pyrophosphate
(VI)
CH 2 OP0 2 H-OPOoH
I
CH 2
I
-» C-CHo
II
CH,
Isopentyl
pyrophosphate
(VII)
COOH
Farnesenic acid
(VIII)
Squalene
(IX)
FIG. la. Reaction sequence showing substances which may be intermediates in
the biosynthesis of squalene from acetate.
(14). This substance was first recognized as a factor which could replace acetate in certain strains of lactobacilli. It is also very efficiently
converted to cholesterol by rat liver (15). When oxygen is excluded,
only squalene is formed (16). Degradation of squalene prepared from
2-C
14 -mevalonic acid showed that it contained six atoms of C
14 per
JAMES K. GRANT
OH
CH 3
I
I
CoASCO-CH 2 -C-CH 2 -COSCoA
► HOCH 2 -CH 2 -C-CH 2 -COOH
I
I
CH 3
OH
β -Methyl- ß -hy droxyglutary 1-Co A
(IV)
Mevalonic acid
(V)
CHXOSCoA
OH
I
HOOC-CH 2 -C-CH 2 -CH 2 OP0 2 H
I
I
CH 3
0
P0 3 H 2
Mevalonic acid
5-pyrophosphate
(VI)
CH 2 OP0 2 H-OPOoH
I
CH 2
I
-» C-CHo
II
CH,
Isopentyl
pyrophosphate
(VII)
COOH
Farnesenic acid
(VIII)
Squalene
(IX)
FIG. la. Reaction sequence showing substances which may be intermediates in
the biosynthesis of squalene from acetate.
(14). This substance was first recognized as a factor which could replace acetate in certain strains of lactobacilli. It is also very efficiently
converted to cholesterol by rat liver (15). When oxygen is excluded,
only squalene is formed (16). Degradation of squalene prepared from
2-C
14 -mevalonic acid showed that it contained six atoms of C
14 per