Resolution of the Phytanic Acid 훼-Oxidation pathway: Identification of Pristanal as product of the decarboxylation of 2-Hydroxyphytanoyl-CoA

1. Introduction
• Phytanic and pristanic acids
are know as branched-chain
fatty acids.
• Phytanic and pristanic acids
exist in small amounts of dairy
product, milk and tallow of
ruminant.
• They are biologically-
functional fatty acids can
prevent metabolic syndrome,
type 2 diabetes or regulatory
function of lipid and glucose
metabolism

2. • Phytanic acid
(C20H40O2)
• Pristanic acid
(C19H38O2)
Phytanic acid is degraded by 𝛼–oxidation
to produce pristanic acid
Accumulated too much
Phytanic acid
Neurological
damage
The degradation of Phytanic acid is considered
• Improving 𝜶–oxidation
• Alternative way (𝝎-oxidation)

3. Resolution of the Phytanic Acid
𝛼-Oxidation pathway:
Identification of Pristanal as
product of the decarboxylation
of 2-Hydroxyphytanoyl-CoA
N. M. Verhoeven, D. S. M. Schor, H. J. ten Brink, R. J. A. Wanders, and C. Jakobs
Department of Clinical Chemistry, Free University Hospital, Amsterdam, The
Netherlands; and Departments of Clinical Chemistry and Pediatrics, University of
Amsterdam, Academic Medical Centre, Amsterdam, The Netherlands

4. In this study,
Pristanal is
produced from 2-
hydroxyphytanoyl-
CoA and undergoes
NAD+ dependent
oxidation to produce
Pristanic acid in
human liver is
considered.

5. Methods
• Homogenized human liver was incubation to produce
pristanic acid
• Each 200 𝜇l of NAD+ was added after 0, 10, 30, 60 and 120
minutes through incubation
• Dodecylaldehyde was added as internal standard.
• Then they were analyzed by gas chromatography (for
pristanal-ethoxime m/z 326 was monitored, for
dodecylaldehyde-ethoxime m/z 228 was monitored)

6. Mass fragmentogram of an extract from the incubation medium of human
liver homogenate incubated at t=0
NAD+ was added
Pristanal

7. Mass fragmentogram of an extract from the incubation medium of
human liver homogenate incubated at t=100
NAD+ was not added
Pristanal

8. When NAD+ is
added
 pristanal is
absent
 pristanic acid is
present
Absent of NAD+
Present of NAD+

9. 𝛼-oxidation pathway
Pristanal is converted
into pristanic acid in a
NAD+ dependent
reaction

10. Characterization of phytanic
acid 𝜔-hydroxylation in
human liver microsomes
J.C. Komen, M. Duran, R.J.A. Wanders
Laboratory Genetic Metabolic Diseases, Departments of
Clinical Chemistry and Pediatrics, Emma Childrens Hospital,
University of Amsterdam,
Academic Medical Center, P.O. Box 22700, 1100 DE
Amsterdam, The Netherlands

11. Introduction
Phytanic acid can be degrade by an alternative way:
𝜔-oxidation.
Phytanic acid is hydroxylated by cytochrome P450
enzyme produce 𝜔- and (𝜔-1)-hydroxyphytanic acid
Phytanic acid
𝛼-oxidation
ω-oxidation
x

12. Method
• Extracts of human and rat liver microsomes were
incubated under different conditions to optimize the
𝜔 -hydroxylation: methyl-𝛽-cyclodextrin, pH and
NADPH concentration.
• The inhibitory effect of azole antimycotics on 𝜔-
hydroxylation was also measured.
• The 𝜔-hydroxylation in different conditions was
analyzed by gas chromatography mass spectrometry

13. The effect of the phytanic acid concentration on the formation of
𝜔-hydroxyphytanic acid (𝜔-HPA)
•
𝑚ethyl−𝛽−cyclodextrin
phytanic acid
is constant
• pH = 7.7
• NADPH = 1mM

14. • Imidazole antimycotics effect on 𝜔-hydroxylation as inhibitors
• Imidazole derivatives: bifonazole, clotrimazole, ketoconazole, and
miconazole inhibit the 𝜔-hydroxylation.
Effect of different imidazole antimycotics on the 𝜔- and (𝜔-1)-
hydroxylation of phytanic acid.

15. Conclusion
Phytanic acid is accumulated too much in body,
will leads to neurological damage.
Therefore, phytanic acid need to be degraded.
In 𝜶-oxidation pathway, Pristanal is converted
into pristanic acid in a NAD+ dependent reaction
𝝎-oxidation is an alternative degradation route
for phytanic acid.
• 𝜔-oxidation produces 2 products 𝜔- and (𝜔-1)-
hydroxyphytanic acid under some optimum
conditions
• 𝜔-oxidation is inhibited by imidazole antimycotics

16. Thank you for your attention