CLINICAL CASES
333
Acyl-CoA
synthetase
transferase I
< (CPTI)
J
Fatty acyl-CoA
Carnitine
AMP + PP
ATP
Cytosol
CoA
Fatty
Fatty
acid
acyl-CoA
Outer
palmitoyl-
mitochondrial
membrane
CoA
Fatty acylcarnitine
Carnitine
Intermembrane
Space
Carnitine
Carnitine
palmitoyl-
transferase II
Inner
mitochondrial
membrane
acylcar-
nitine
translocase
CPT II
Matrix
/
F
Fatty acyl-CoA
3-oxidation
Figure 36-4. The activation of fatty acids and transport into the mitochondrion
via the carnitine shuttle.
(Reproduced, with permission, from: D.B. Marks, et al.,
Basic Medical Biochemistry: A Clinical Approach,
Philadelphia: Lippincott
Williams & Wilkins, 1996:361.)
cleaved by P-ketothiolase producing one molecule of acetyl-CoA and a new
activated fatty acyl-CoA, two carbon atoms shorter than at the outset in a reac-
tion that requires another molecule of free CoA. The newly produced fatty acyl-
CoA repeats the cycle of steps in P-oxidation releasing another acetyl-CoA and
onward until the last cleavage step that hydrolyzes acetoacetyl-CoA to two
molecules of acetyl-CoA.
While the postfeeding fast represents a normal state reflective of the alter-
nation of feeding and not feeding, the starvation state shown in Figure 36-5
represents an abnormal state and reflects a dramatic increase in the metabolic
changes observed in the postfeeding state, illustrated in Figure 36-3. Thus star-
vation represents an intensification of the metabolic adjustments of the fasting
state with some significant differences seen only in prolonged starvation.
Two marked changes in plasma concentrations occur, a decrease in glucose
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