BC2002 lecture 10

versatile, vital

β-oxidation is very ______ and ______ for energy

β-oxidation

Essential metabolic source of energy during fasting and periods of nutrient deprivation

β-oxidation

vital metabolic source of energy and water during hibernation

triacylglycerols, β-oxidation

camels have a huge store of _______ in the hump, ______ is a metabolic source of energy and water under desert conditions

Diet, stored fats, newly synthesized fats

fatty acids for catabolism obtained from 3 sources. ______, ______, and ______

stored fats

fatty acids as triacylglycerols in adipocytes are

newly synthesized fats

triacylglycerols that body synthesizes are

adipocytes

cells that are specialized to store triacylglycerol fats

triacylglycerols

________ stored in adipocytes rich source of energy

triacylglycerols (TAG)

3 long-chain fatty acid chains esterified to glycerol backbone

liver, heart, raising skeletal muscle

triacylglycerols provide >50% of energy in _______, ______, and _______

triacylglycerol

more reduced and much less hydrated than glycogen, so can stockpile large quantities in adipocytes, sole energy source in hibernating animals

3 stages

Fatty acid catabolism occurs in ______ just like carbohydrate catabolism

acetyl-CoA, β-oxidation, mitochondrial matrix

During the first stage of fatty acid catabolism, long chain fatty acids catabolized to form acetyl units in form of _______ called _______. occurs in _________

oxidized

During the second stage fatty acid catabolism, acetyl groups are ______ in citric acid cycle

mitochondrial respiratory chain, phosphorylation

during the third stage of fatty acid catabolism, electrons derived from oxidation of stages 1 and 2 pass to O2 via the __________ ATP synthesis by _________

adipocytes

During the first stage of fatty acid oxidation, mobilization of triacylglycerols from ________

mitochondrial matrix

during the second step of fatty acid oxidation fatty acid activation and transport to ________ occurs

β-oxidation pathway

the third step of fatty acid oxidation is the

TAG

During the first step of oxidation ____ fats must be mobilized from storage adipocytes

lipid droplets, phospholipids, perilipin

TAGs stored within _______ of TAGs and sterol esters, surrounded by monolayer of _______, surface of droplet coated with protein _________, a protein which restricts untimely access to TAGs

adipocytes, adenylyl cyclase, activate PKA

secreted in response to low blood (glucose) to bind receptors on _______ and activate _______ to increase (cAMP) which activates ______

perilipins, lipases

PKA phosphorylated ______ and other proteins that open the lipid droplet, allowing activity of 3 cytosolic ______ including hormone sensitive ones, these degrade TAGs to finallly liberate fatty acids

ester linkages

All the lipases hydrolysis _______ in tri/di/mono -acyl glycerols, liberates fatty acids and glycerol

serum albumen

fatty acids —> blood—> bind _______ carried to tissues which need energy e.g. liver, skeletal muscle, renal cortex and enter via fatty acids transporter protein

fatty acid transporter, energy, mitochondria

In the second step, fatty acids dissociate from serum albumen and go through __________ protein into cytosol of cells which need ____ but fatty acid β- oxidation occurs in ______

mitochondria, mitochondrial membrane

fatty acid chains <14 carbons length can enter ______, most fatty acid chains are >14 carbons have to be helped into it. By activation and use of enzymes and transporter protein into inner _________

CoA, fatty acyl-CoA synthetase

Fatty acids activated/energized by _____ addson using _______ isoenzymes

Fatty acyl-CoA synthetase, fatty acyl-CoA

Catalyze formation of thioester linkages between fatty acid carboxyl group and thiol group of coenzyme A to yield a ________ coupled to ATP cleavage

fatty acids

Fatty acyl-CoA is a high energy compound now much more amenable to catabolism than _____

carnitine shuttle

fatty acyl transport into mitochondrial matrix is called the

-OH of carnitine, carnitine acyl-transferase-1

Fatty acyl-CoA bond hydrolyzed and fatty acyl group attaches to ______ in outer mitochondrial membrane catalyzed by _________

carnitine transporter

fatty acyl-carnitine enters mitochondrial matrix through _________ on inner mitochondrial membrane

inter membrane space

Carnitine re-enters ________ and process starts again

acetyl-CoA, 8 Acetyl-CoA, 4 enzymes

overall in β-oxidation each 2C of fatty acyl-CoA cleaved and converted to ______, 16C palmitoyl-CoA —> ________, _______ needed for formation of each acetyl CoA that is cleaved off during β-oxidation.

dehydrogenase, hydratase, dehydrogenase, thiolase

what are the four enzymes needed for β-oxidation?

FAD, FADH2, FADH2

β-oxidation pathway. dehydrogenase removes 2H+ to _____—>______. double bond produced between α and β carbon-1 _____ formed

α and β double bond

β-oxidation pathway. Hydrotase H2O added to ______, 1 H2O input

NADH + H+ -1 NADH and H+ formed

β-oxidation pathway. dehydrogenases removes 2H+ from β-carbon to NAD+ —>

thiolysis

using thiolase, splitting off of terminal acetyl CoA with entry of new CoA-SH and 1 Acetyl CoA formed and 1 CoA input

7 times

How many times in total are the 4 steps of β-oxidation carried out for the complete conversion of 16 C palmitoyl-CoA to 8 molecules of Acetyl-CoA?

C16 palmitoyl-CoA, C14 myristoyl-CoA

goes through 4 enzyme steps of β- oxidation —> 1 acetyl-CoA made and _______ fatty acyl-CoA left

acetyl-CoA, 3C propionyl-CoA, 3 enzymatic

β-oxidation process repeats 6 more times and 6 more _____ made and one left at end, if fatty acyl chain has an odd number left with ______ this breaks down further in _______ steps

7FADH2 and 7NADH

Lots of energy obtained via β-oxidation, ________ deliver electrons to respiratory chain and 8 acetyl CoA enter citric acid cycle

-9800 kJ/mol for complete oxidation of 1 palmitate

β-oxidation ΔG’0=

unsaturated fatty acids

many fatty acids have double bonds-

one position

monounsaturated = in ______

>1 position

poly unsaturated in ______

double bonds

Extra enzymes needed to catabolize fatty acids with ______ during β-oxidation

isomerase, reductase

converts cis to trans, in PUFAs need extra _____ enzyme