BIOCHEM 2: Oxidation of other FA's and Ketogenesis

triacylglycerols from plant oils

What are some sources of unsaturated FA?

cis

All naturally occurring unsaturated FAs have their double bonds in the __________ configuration.

1. monounsaturated

2. polyunsaturated

What are the two groups of USFA?

YES

Do the saturated carbons of the monoSFA get oxidized the same way as a normal SFA?

3

How many regular saturated cycles does it take to oxidize the first saturated part of the oleic acid?

1. moves the double bond on carbon to the right

2. converts cis to trans

What 2 things does enoyl CoA isomerase do?

because now hydratase can hydrate this oleic acid because its on carbon 2 and trans

Why is converting a double bond from cis to trans so important?

NO

Is enoyl CoA isomerase needed for the oxidation of SFA's?

False

True or False: The enoyl CoA isomerase enzyme requires cofactors and ATP?

true

True or False: Mono-unsaturated FAs provide us with the same number of ATPs as their saturated counterparts with the same number of carbons.

monounsaturated FA oxidation

just like a monoUNSFA

In this poly UNSFA how does this first double bond (red) go through oxidation?

reductase enzyme

What does reaction 1 get catalyzed by?

adds a hydrogen on carbon 5 and carbon 2 to make a new double bond on carbons 4+3

What does 2,4-dienoyl CoA reductase do?

1. moves the double bond from carbon 3 to carbon 2

2. converts it to trans

What does 3,2-enoyl CoA isomerase do?

reductases

this is a group of enzymes that reduce a substrate by adding hydrogens

1. FADH2

2. NADH

What cofactors to reductases require?

true

True or False: FAs with odd number of carbons are oxidized the same way as their even counterparts to produce acetyl CoA molecules ONLY up to the very last oxidation cycle where we start with a five carbon fragment

1. propionyl CoA

2. acetyl CoA

What are the two products from oxidation of FA with an odd number of carbons?

succinyl CoA

What does propionyl CoA need to turn into in order to recycle back into the citric acid cycle?

citric acid cycle (indirectly for the propionyl CoA)

Where do these two products feed into?

carboxylases

these are enzymes that add a carboxyl group to their substrates

1. ATP

2. biotin (B7)

What cofactors to carboxylases require?

energy consuming

Because carboxylases hydrolyze ATP, carboxylation reactions are ______________ reactions

racemases

these are the enzymes that interconvert between the R and S isomers of chiral molecules

NO

Do racemases require cofactors or ATP in the formation of succinyl CoA from propionyl CoA?

mutase

these are enzymes that shift functional groups from one carbon to a directly adjacent carbon

B12

What cofactor does mutase require?

1. B7

2. B12

What vitamins allows us to utilize FAs with an odd number of carbons for energy production.

FA with odd number of carbons oxidation

because succinyl CoA enters the cycle halfway thru

Why is the ATP yield from succinyl CoA less than that from acetyl CoA?

acetyl CoA

What are the products from all even carbon FA?

1. propionyl CoA

2. acetyl CoA

What are the products from all odd carbon FA?

riboflavin (B2)

What is used to make FAD?

niacin (B3)

What is used to make NAD?

brain cells do not make the enzymes needed

Why do brain cells NOT OXIDIZE FA to acetyl CoA?

1. glucose

2. ketone bodies

When _______ and _____________ are not available, the brain will shut down, and the person will go into a coma?

Ketogenesis

This is a group of reactions that occur when glucose level drops and its purpose is to provide ketone bodies for brain cells to maintain the citric acid cycle and make ATP

mitochondria of liver cells

Where do ketogenesis reactions occur in?

true

True or False: Ketone bodies are only made by the liver (due to need HMG CoA synthase)

1. acetoacetate

2. beta-hydroxybutyrate

3. acetone

What are the 3 molecules that make up a ketone body?

acidic due to carboxyl group

Are ketone bodies acidic or basic and why?

severe systemic acidosis

If ketone bodies are released into circulation in large amounts, what can happen?

ketogenesis

thiolase

The first rxn is a condensation rxn of 2 acetyl CoA's and is catalyzed by ___________________

HMG CoA synthase

The second rxn is also a condensation rxn involving a third acetyl CoA molecule being added by ____________

NO

Does HMG CoA synthase require ATP?

liver

HMG CoA synthase is a ________ enzyme.

splits HMG CoA to acetyl CoA and acetoacetate

In the 3rd rxn, what does HMG CoA lyase do?

dehydrogenase

What kind of enzyme would catalyze this rxn?

acetone

When we are running out of glucose, large amount of ketone bodies will be produced, which then means large amount of _______ will be excreted in our breath giving it a fruity stench to it.

so the brain can convert them to acetyl CoA

What is the reason for making ketone bodies?

ketone bodies converted to acetyl CoA

ketoacyl CoA transferase

this is an enzyme that is made by the brain and all other tissues EXCEPT the liver

succinyl CoA

What does ketoacyl CoA transferase require in order to transfer a CoA onto the acetoacetate?

lose weight because cell cannot import glucose without insulin, making the body use it's "emergency fuel"

If a diabetic patient is not taking insulin, will they gain or lose weight—and why?

yes by making a patient fast, or a very low carb diet, or prolonged intense exercise

Can you induce ketogenesis in normal healthy individuals? How?

1. To enter ketogenesis, the body must mobilize and oxidize stored fatty acids.

2. This increases lipolysis and fatty acid oxidation, reducing adipose mass.

How could ketogenesis help obese patients lose weight?