Synthesis of Ketone Bodies (2)

8/7/2019 Synthesis of Ketone Bodies (2)

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KETONE BODIESKETONE BODIESGROUP MEMBERS:

SYAZANA BT MOHAMAD ZAHRI

HARYATI A/P AKIT

NURNAJUWA BT MOHD RASID

ASMA ANATI BT CHE MAT SERI

NURSYUHAIDA AMIRA BT ABDULLAH

ADIBAH FARLIYANA BT AMINORDIN WAN ROZANA BT WAN AHMAD

LIYANA BT JALALUDDIN


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INTRODUCTIONINTRODUCTION

Ketone bodies are three water-soluble compounds:

produced as by-products when fatty acids are broken down

for energy in the liver and kidney. used as a source of energy in the heart and brain (vital

source during fasting/starvation for brain)

The three endogenous ketone bodies are :

Acetone

Acetoacetate

beta-hydroxybutyric acid


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SYNTHESIS OF KETONE BODIES


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Synthesis from acetyl CoA: Step 1


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Synthesis from acetyl CoA:Synthesis from acetyl CoA:

Step 2Step 2


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Synthesis from acetyl CoA:Synthesis from acetyl CoA:

Step 3Step 3

Acetoacetate


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SynthesisSynthesis from acetyl CoAfrom acetyl CoA: Acetoacetate ,Acetone,: Acetoacetate ,Acetone, BetaBeta--hydroxybutyratehydroxybutyrate..


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REGULATION OF KETONE

BODIES


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Ketogenesis may or may not occur, depending on levels ofKetogenesis may or may not occur, depending on levels of

available carbohydrates in the cell or body. This is closely relatedavailable carbohydrates in the cell or body. This is closely related

to the paths of acetylto the paths of acetyl--CoA:CoA:

y When body has ample carbohydrate

= Glucose is completely oxidized to CO2

= acetyl-CoA is formed as a intermediate

When the body has excess carbohydrate is available

= some glucose is fully metabolized, some of it is stored by using acetyl-CoA to create fatty acid

When the body has no free carbohydrates available

= fat must be broken down into acetyl-CoA in order to get energy= Acetyl-CoA is not being recycled through the citric acid cycle

= Instead it will go through ketone body synthesis pathway


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USES OF KETONE BODIESUSES OF KETONE BODIES

BRAIN

HEART

SKELETAL MUSCLE


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USED AS ENERGYUSED AS ENERGY Acetoacetate and beta-hydroxybutyrate reconverted to acetyl-coA to produce

energy ; via citric acid cycle.

Emphasize in brain and heart.

Heart sets little energy from ketone bodies except special circumstances , it uses

mainly fatty acids. But it prefers use acetoacetate as source of energy compared toglucose.

Brain gets its energy from ketone bodies when glucose less available;level of

insulin decrease, (e.g. : when fasting),

In the event of blood glucose decrease, most other tissues have additional energysources beside ketone bodies but the brain does not.

For 3 days brain get 30% from ketone bodies, after 40 days, it goes up 70%

(during initial, brain does not burn ketone bodies since lipid synthesis in brain is

important)


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DISEASEDISEASE


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DIABETIC KETOACIDOSISDIABETIC KETOACIDOSIS

y Definition: complication of diabetes that

occurs when the body cannot use sugar

(glucose) as a fuel source because the

body has no insulin or not enough insulin,and fat is used instead.

y As result, by-products of fat breakdown,called ketones, build up in the body.


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Types of diabetesTypes of diabetes

Type 1

y Lack enough insulin

y Missing doses of insulin can also lead to ketoacidosis

in people with diabetes.

y OAA is low, due to excess gluconeogenesis, so

acetyl-CoA from fat/protein catabolism does not goto TCA, but rather to ketone body production

y Acetone can be detected on breath of this type of

diabetes


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The cells cannot absorb glucose properly although

glucose levels in the blood become elevated.

With insulin resistance, the body makes excess

insulin but the muscle, liver, and fat cells do not use

or respond properly to insulin.

The receptor may become insensitive towards

insulin so no glucose absorption by cell.

Type 2


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KETONURIAKETONURIA

y Medical condition when there are

presence of ketone bodies in urine.

y Result of using fat as energy source thus

ketone bodies form and accumulate in the

body.

y Ketone appear in urine at large amount

than normal.


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THATS ALL.

THANK YOU!!

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Synthesis of Ketone Bodies (2)