Fate of Glucogenic and Ketogenic amino acid Amino acid are the currency of of nitrogen and protein economy of the host, hence they are used in many pathways beyond protein synthesis, including energy production and neurotransmitter synthesis. All amino acid are comprised of an amino group and a carbon skeleton. During metabolism these two parts are separated as they have different ‘fates’ Of the liberated amino acid approximately 75% are utilized while remainder serve as precursors for important biological compound and those not utilized are degraded to amphibolic intermediates The pathway of amino acid catabolism is quite similar in most organism

1. FATE OF GLUCOGENIC AND
KETOGENIC AMINO ACID
Class- Bsc bioscience 6th semester
Section – D

2.  Amino acid are the currency of of nitrogen
and protein economy of the host, hence
they are used in many pathways beyond
protein synthesis, including energy
production and neurotransmitter synthesis.
 All amino acid are comprised of an amino
group and a carbon skeleton. During
metabolism these two parts are separated
as they have different ‘fates’
 Of the liberated amino acid approximately
75% are utilized while remainder serve as
precursors for important biological
compound and those not utilized are
degraded to amphibolic intermediates
 The pathway of amino acid catabolism is
quite similar in most organism

3. Site of amino acid metabolism
 Intestine- amino acid from protein digestion are
absorbed. Intestine preferably uses glutamine and
asparagine as energy supplier, product formed
with remaining amino acid are sent to liver via
portal vein
 Liver- all amino acid except branched chain
catabolism start here.The amine group is
seprated and incorporated in urea and carbon
skeleton is either oxidized in CO2 and H2O or
used for gluconeogenesis and ketogenesis
 Muscle- degradation of branched chain amino
acid start in skeletal muscle.The amine group are
transferred to pyruvate to form alanine. The
muscle amino acid released in circulation are
mainly alanine and glutamine that act as carriers
of amine from other tissue
 Kidney- organ captures glutamine released from
muscle and catabolized it to release ammonium
with help of glutaminase and glutamte
dehydrogenase

4. Overview of metabolism
of amino acid
.
Deanimation- amino group is
removed from the carbon skeleton
and transferred to α-ketoglurate,
which release glutamate
The carbon skeleton are converted
to intermediates of mainstream
carbon oxidation pathways via
specific adaptor pathway
Surplus nitrogen is removed from
glutamate, incorporated into urea,
and excreted

5. Fate of amino
group
Synthesis of
new
biomolecules
biosynthesis of
amino acids
Biosynthesis of
biological
amines
Biosynthesis of
nucleotides
Dopamine
Histamine , etc
Excreted
through the urea
cycle in form of
Uric acid Uricotelic
organism
Ammonia
ammonotelic
organism
Urea
ureotelic
organism

6. •It is first step of L-amino acid catabolism
•Most common amino acid (except lysine,
threonine and imino acid) can be converted
into corresponding keto acid by
transamination
•In this the α-amino group is transferred to
the α-carbon atom of α-ketoglutarate, leaving
behind the corresponding α-keto acid analog
of the amino acid,
•There is no net deamination in these reaction
because the α-ketoglutarate becomes
aminated as the α-amino acid is deaminated
•It is reversible and catalyzed by
Transaminase or amino transferase.
•The effect of transamination reactions is to
collect the amino groups from many different
amino acids in the form of L-glutamate

7. Pyridoxal phosphate and Aminotransferase
•All aminotransferase require the
prosthetic group Pyridoxal
phosphate(PLP) which is derived from
Pyridoxine(vitamin B6)
•Pyridoxal phosphate is generally
covalently bound to the enzyme’s active
site through an aldimine (Schiff base)
linkage to the ε-amino
group of a Lys residue
•Pyridoxal phosphate participates in a
variety of reactions at the α, β, and γ
carbons (C-2 to C-4)
of amino acid
•It undergoes reversible transformation
between aldehyde form(pyridoxal
phosphate) and animated
form(pyridoxamine phosphate)
Pyridoxal phosphate, the prosthetic group of
aminotransferases (a) Pyridoxal phosphate
(PLP) and its aminated form, pyridoxamine
phosphate

8. Reaction at α- carbon
Transamination(bimolecular ping pong reaction)- steps are
1st step:Transfer of amino group from
amino acid to PLP to form
pyridoxamine relasing keto acid
Role of PLP- bond of α carbon of the
substrate is broken, removing either a
proton or a carboxyl group leaving behind
electron pair at α carbon forming
unstable carbanion, that is stabilized by
pyridoxal phosphate by resonance
through conjugated structure
Second step- α-ketoglutarate reacts
with pyridoxamine phosphate to form
glutamate
Decarboxylation
Racemization ( interconverting L- and D-amino acid)

9. Oxidative deamination of Glutamate
 The nitrogen atom that is transferred to
α-ketoglutarate in transamination
reaction forming glutamate is concerted
into free ammonium ion by oxidative
deamination
 This reaction occur in hepatocytes cell
mitochondria
 Reaction is catalyzed by glutamate
dehydrogenase that is located in
mitochondria.This enzyme is unusual in
being able to utilize either NAD+ or
NADP+
 L-glutamate is the only amino acid that
undergoes oxidative deamination at
appreciable rate
 The ammonia released is incorporated
into urea by urea cycle

10. Role of glutamate dehydrogenase
 Their activity is allosterically regulated
 Enzyme consist of six identical sub-unit
 Guanosine triphosphate(GTP) and
Adenosine triphosphate(ATP) are
allosteric inhibitors, whereas
Guanosine diphosphate(GDP) and
Adenosine diphosphate(ADP) are
allosteric activators
 Hence, lowering of a energy
charge(more ADP or GDP) accelerates
oxidation of amino acids favouring
formation of α-ketoglutarate that can
be channeled towardsTCA cycle for
complete oxidation to provide energy

11. Transdeamination
 Since majority of transamination reaction is α-
ketoglutarate is acceptor keto acid forming
glutamate, that is oxidatively deaminated in liver by
glutamate dehydrogenase forming α-ketoglutarate
and ammonia
 Conversion of α-amino nitrogen to ammonia by
concerted action of GDH is termed as
‘transdeamination’
 Thus transamination and deamination are coupled
process though they occur at distant places

12. GLUCOSE AND ALANINE CYCLE
It is interorgan cycle that piggybacks on Cori cycle and accomplish net transport
of nitrogen from muscles and other peripheral tissue to liver
Pyruvate produced isn’t reduced to lactate (as in cori cycle) but transaminated
to alanine which is transported to liver
In liver transamination is reversed and pyruvate is converted to glucose by
glycogenesis releasing glucose in bloodstream

13. •Glutamine is most abundant amino acid and is significant as
nitrogen and amino acid carrier
•It brings net transfer of nitrogen from peripheral tissue to liver in
exchange of glutamate
•The enzyme involved are transaminase, glutamate dehydrogenase,
glutamate synthetase and glutaminase.

14. Fate of carbon
skeleton
The carbon skeleton is the α-keto acid
remaining after removal of ammonia
from amino acid.
It have following fates-
1. Biosynthesis of non-
essential amino acid by
transamination with
glutamic acid
2. Converted into 7 common
metabolites:- pyruvate,
acetyl-CoA, acetoacetate, α-
ketoglurate, succinyl-CoA,
fumurate, oxaloacetate that
are precursors to glucose or
citric acid cycle
intermediates
The carbon skeletons of amino acids
enter the citric acid cycle through five
intermediates: acetyl-CoA, α-
ketoglutarate, succinyl-CoA, fumarate,
and oxaloacetate

15. Classification of amino acid
based on metabolic pathway
Glucogenic amino acid- those that give rise to a net
production of pyruvate ofTCA cycle intermediates,
such as alpha- ketoglutarate, succinyl CoA,
Fumurate and oxaloacetate, all of which are
precursors to glucose via gluconeogenesis
Ketogenic amino acid- they are converted to ketone
bodies(acetylCoA or acetoacetylCoA) via
ketogenesis.They enter kreb’s cycle to produce
energy
Some amino acid are both glucogenic and
ketogenic.

16. 6 Amino acid degraded to
pyruvate
1. Alanine- on direct transanimation
2. Cysteine- in two step, one removes sulphur other
transanimation
3. Serine- concerted to pyruvate by serine dehydratase
both β-hydroxyl and α-amino acid are removed in it
4. Tryptophan- cleaved into alanine then pyruvate
5. Glycine- conveted into serine via addition of
hydroxymethyl group than to pyruvate
6. Threonine- converted to2-amino-3-ketobutyrate than
glycine and at last pyruvate

18. 7 Amino acid degraded to acetyl CoA
and acetoacetal CoA
 Tryptophan-breakdown is most complex, portions of
tryptophan (four of its carbons) yield acetyl-CoA via
acetoacetyl-CoA Some of the intermediates in tryptophan
catabolism are precursors for the synthesis of other
biomolecules including nicotinate, a precursor of NAD and
NADP in animals; serotonin, a neurotransmitter in vertebrates
etc
 Lysine
 Phenylalanine- and its oxidation product tyrosine are
degraded into two fragments, one converts to acetoacetate
which is converted to acetyl-CoA, and other to fumarate both
of which can enter the citric acid cycle
 Leucine
 Isoleucie- Final step of leucine, lysine and tryptophan
resembles step in oxidation of fatty acid
 Threonine

20. 5 Amino acid degraded to α-
ketoglutarate
1. Proline-its cyclic structure is opened by oxidation of the
carbon distant from the carboxyl group creating Schiff
base, whose hydrolysis form a linear semialdehyde which
is further oxidized at the same carbon to produce
glutamate
2. Glutamine- converts to glutamate by donating its amide
group to aceptor b y action of glutaminase or other
enzymes
3. Glutamate-Transamination or deamination of
glutamate produces α-ketoglutarate
4. Arginine- is converted to ornithine which is
transanimated to glutamate γ-semialdehyde which then
converted to glutamate
5. Histidine- its conversion to glutamate occur in multiple
step

22. 4 Converted to succinyl-CoA
 Methionine-donates its methyl group to possible acceptor
through S-adenosylmethionine and 3 of its 4 carbon
converted to propionate of propionyl-CoA, a precursor of
succinyl-CoA.
 Isoleucine -undergoes transamination, followed by
oxidative decarboxylation of the resulting α-keto acid.The
remaining five-carbon skeleton is further oxidized to acetyl-
CoA and propionyl-CoA.
 Valine-undergoes transamination and decarboxylation,
then a series of oxidation reactions that convert the
remaining four carbons to propionyl-CoA
 Threonine-is also converted in two steps to propionyl-CoA
 Propionyl-CoA derived from these three amino acids is
converted to succinyl-CoA via series of step

24. Branched chain amino acid degradation
 Valine, Isoleucine,
Leucine are BCAA that
are oxidized as fuel
mainly in muscles,
kidney, brain tissue and
adipose
 Oxidation of them are
similar
 Oxidized to
1. valine to succinyl-CoA-
Glucogenic
2. Isoleucine to succinyl-
CoA and acetyl-CoA-
gluco and ketogenic
3. Leucine to acetyl CoA-
ketogenic

25. Aspargine And Asparate Degradation
 Their carbon skeletons enter the citric
acid cycle as malate in mammals or
oxaloacetate in bacteria.
 The enzyme asparaginase catalyzes the
hydrolysis of asparagine to aspartate,
which undergoes transamination with α-
ketoglutarate to yield glutamate and
oxaloacetate
 The oxaloacetate is converted to malate
in the cytosol and then transported into
the mitochondrial matrix through the
malate–α-ketoglutarate transporter in
mammals
 In bacteria oxaloacetate produced in the
transamination reaction can be used
directly in the citric acid cycle

26. Research paper
Inhibition Of Amino Acid
Metabolism Selectively
Targets Human Leukemia Stem
Cells
by-
Courtney L. Jones1, Brett M. Stevens1, Angelo D'Alessandro1,2, Julie A. Reisz2, Rachel Culp-Hill2,
Travis Nemkov2, Shanshan Pei1, Nabilah Khan1, Biniam Adane1, Haobin Ye1, Anna Krug1, Dominik
Reinhold3, Clayton Smith1, James DeGregori1,2, Daniel A. Pollyea1, and Craig T. Jordan1

27. Overview
 By studying the metabolome of human acute myeliod
leukemia (AML) we found that amino acid
metabolism(AAM) increases in the leukemia stem cell(LSC)
 LSC obtained from de novo AML patient rely on amino acid
for oxidative phosphorylation and survival
 So pharmacological inhibition of AAM can cause reduced
oxidative phosporylation (OXPHOS) and causes death
hence, drugs that target AAM vulnerability can be
used(like Venetoclax and azacitidine)
 LSC obtained from relapsed AML patient can compensate
their AAM through increased fatty acid metabolism

28. Introduction
 Conventional chemotherapy ofAML patient can cause
relapse
 It was found that cancer stem cells (CSCs) dependent on
OXPHOS and have low glycolytic reserves compare to
mature cells.
 Increased level of OXPHOS in CSCs can promote
chemotherapy resistant
 LSCs in addition to above show specific metabolic
properties like low level of reactive oxygen species,
increased branched chain amono acid metabolism etc.
these unique metabolic properties can be used to improve
therapy for AML patients
 In this research it was demonstrated that inhibition of
OXOPHOS is key determinant of LSC eradiction

29. Result
 In LSC 39 metabolites were more in amount than AML blasts
including 16 amino acids, 5 glutathione homeostasis
metabolites and 2 TCA cycle intermediates which all are
related to AAM
 LSC show high uptake and utilization of amino acid than AML
blasts particularly for Glutamine, Glutamate and proline
 Amino acid depletion causes decreased colony formation by
LSCs while AML blasts and HSPCs showed no effect.
 LSCs viability wasn’t much effected by the other metabolites
in comparison to amino acid
 LSCs is selectively sensitive to loss of amino acid as they are
less metabolically flexible
 BCL2 inhibition may reduce the AAM suppressing OXOPHOS.
BCL2 inhibitors venetoclax with azacitidine reduce AAM and
also amino acid uptake in LSCs is mechanism for LSCs
eradication
 Relapse LSCs escape amino acid loss by increasing fatty acid
metabolism

30. Conclusion
Metabolomic differences between LSCs and bulk AML cells were studied and it was found that
amino acid metabolism was essential for survival of LSCs and metabolism of specific amino acid
(cysteine, glutamine and branched amino acid) are essential in multiple hematologic malignancies
Role of AAM for OXOPHOS is also established in LSCs
LSCs are more dependent OXOPHOS compared to AML blasts or normal HSPCs which are dependent
on glucose
Ventoclax with azacytidine treatment can target amino acid metabolism in LSCs in AML patient
These findings validate the potential of targeting metabolic vulnerabilities of cancer stem cells in
patients