PHA6112 LEC: Lipid Metabolism

Cytosol

Lipogenesis Site

Multi-enzyme complex - fatty acid synthase

Lipogenesis Enzyme

Acyl Carrier Protein

Lipogenesis: Carriers of Intermediates

NADPH (reducing agent)

Lipogenesis: Cofactors

+2C at a time

Acetyl CoA to Malonyl CoA

Lipogenesis: Building Up

Mitochondrial Matrix

Lipolysis: Site

Non-complexed enzyme and independent reactions -- Hormone Sensitive Lipase

Lipolysis: Enzyme

Co-enzyme A (CoA)

Lipolysis: Carriers of intermediates

FAD and NAD+ (oxidizing agent)

Lipolysis: Cofactors

-2C at a time

CoA derivatives involved in all steps of FA degradation

Lipolysis - breaking down

Stomach; gastric lipase; chyme

_______ is the first site for lipid digestion using ____________. The resulting TAGs are transported in the small intestine as ________.

Chyme

received by the small intestine

triggers the release of cholecystokinin (CKK)

Cholecystokinin

trigger the release of bile from the gallbladder

Bile

responsible for the emulsification of fatty acids

Pancreatic lipase

further breakdown TAGs to glycerol and FAs

Micelle

mixture of FAs, glycerol, bile;

small enough to be absorbed through the intestines

Chylomicrons

repacked micelles in the small intestines resulting in a new TAG molecule which then forms _______.

Chylomicrons; lymphatic system

_______ is responsible for transporting TAGs into the bloodstream via the _____________

Lipoprotein lipase

breaks down chylomicrons back to TAGs

Liver

where are fats important in the development of nerve and brain tissues transformed?

- Reused and stored as lipids in adipocytes

- Oxidized and converted to acetyl-coa as energy source

When TAGs are broken down by lipases into FAs, the FAs can be:

beneath the skin, abdominal area, vital organs

sites where adipocytes are found

Insulator

shock absorber

functions of adipocytes

Triacylglycerol (TAGs)

major source of stored energy

cAMP

activates hormone sensitive lipase via a series of enzymatic reactions

HSL

works in the initial hydrolysis of TAGs converting it to glycerol and fatty acids

serum albumin

transports FAs and glycerol for B oxidation

Carnitine

transports fatty acid from cytosol to mitochondrial matrix for beta oxidation

Beta oxidation

degrades acyl coa to acetyl coa while producing FADH2 and NADH

cytosol

site for fatty acid synthesis

mitochondrial matrix

site for fatty acid oxidation

3-hydroxy-3-methylglutaryl CoA (HMG-CoA)

product of combining acetyl CoA and acetoacetyl CoA by HMG synthase

Mevalonate pathway

Ketogenesis Pathway

HMG CoA is intermediate for 2 pathways:

Mevalonate pathway

responsible for the cytoplasmic synthesis of sterols and terpenes

HMG-CoA Reductase; statin drugs

_______ is the target enzyme by _______ drugs to inhibit cholesterol synthesis

Monoterpene

2 isoprenes

10 carbons

Diterpene

4 isoprenes

20 carbons

Sesquiterpene

3 isoprenes

15 carbons

Triterpene

6 isoprene

30 carbons

Tetraterpene

8 isoprene

40 carbons

Ketogenesis Pathway

responsible for the production of ketone bodies in the mitochondrion

Acetone

Acetoacetate

B-hydroxybutyrate

Ketone bodies

Ketosis

body shifts dependence from glucose to ketone bodies as energy source

Ketonemia; 20 mg/100 mL

elevated ketone bodies in the blood; level?

Ketouria; 70 mg/100 mL

elevated ketone bodies in the urine; level?

Ketoacidosis

excessive levels of ketone bodies causing blood pH acidification (common in diabetic patients)

tx of epilepsy among children

what was ketogenic diet originally used for