Fatty acid synthase action Flashcards
What is the first part of the first step of FA biosynthesis?
Reaction between Biotin and HCO3 -
What is the useful product formed via the reaction between biotin and HCO3 -?
Biotin-CO2
What enzyme is used in the second part of the first step of fatty acid biosynthesis?
Transcarboxylase
What is the second step of fatty acid biosynthesis?
Chain elongation
How are long chain fatty acids formed?
Additions of acetyl-CoA and malonyl-CoA
Role of acetyl-CoA in chain extension?
Primes the reaction, and becomes the methyl terminus of the fatty acid chain
Role of malonyl-CoA in chain extension?
Each one provides a 2 carbon unit to extend the chain
What is needed for chain extension other than acetyl-CoA and malonyl-CoA?
NADPH and H+
How many NADPH and H+ are needed per malonyl-CoA?
2
Overall reactants for FA biosynthesis (combining steps)?
acetyl-CoA, ATP, NADPH and H+
Reactants for formation of palmitate?
8 acetyl-CoA, 7 ATP, 14 NADPH and 14 H+
Why is 8 acetyl-CoA needed for the formation of palmitate?
1 is needed for the methyl terminus of palmitate, the other 7 are used to make 7 malonyl-CoA
Why is 7 ATP needed for the formation of palmitate?
It is used to make 7 malonyl-CoA from 7 acetyl-C-A
What happens to the CO2 used in the first step of FA biosynthesis?
It is replenished as the second step produces the same amount of CO2 that the first step uses
What are the overall products of FA biosynthesis (combining steps)?
FA, CoA, H20, ADP, PI, NADP+
Overall products of palmitate formation?
palmitate, 8 CoA, 6H2O, 7 ADP, 7 PI and 14 NADP+
What catalyses the second step of FA biosynthesis?
Fatty acid synthase
Where is fatty acid synthetase found?
In the cytosol
How is it known that FA synthase is found in the cytosol?
It is found in the cytosolic fraction of cells
What does fatty acid synthase require in order to work?
Malonyl-CoA, acetyl-CoA and NADPH
First part of first enzymatic step of fatty acid synthase ?
Acetyl-CoA is attached to Acyl Carrier Protein
Reaction of first part of first step of fatty acid synthase?
Acetyl-CoA–> acetyl-ACP + CoASH
Second part of first enzymatic step of fatty acid synthase?
Acetyl group is transferred to the beta-ketoacyl ACP synthase protein/domain
Second enzymatic step of fatty acid synthase?
Malonyl group is transferred to ACP
Enzyme used in second step of fatty acid synthase?
Malonyl transacylase
Third enzymatic step of fatty acid synthase?
Acetyl group that is bound to beta-ketoacyl-ACP synthase is joined to the malonyl ACP molecule
What small molecule is released in the third enzymatic step of fatty acid synthase?
CO2
Fourth enzymatic step of fatty acid synthase?
Reduction of the Beta-ketoacyl-ACP
What functional group is reduced in the fourth enzymatic step of fatty acid synthase?
The carbonyl group furthest away from the S-ACP, to an alcohol
Product of the fourth enzymatic step of fatty acid synthase?
beta-hydroxylacyl-ACP
Enzyme used in the fourth enzymatic step of fatty acid synthase?
beta-ketoacyl ACP reductase
Fifth enzymatic step of fatty acid synthase?
Dehydration of beta-hydroxyacyl-ACP
Which functional group is dehydrated in the fifth enzymatic step of fatty acid synthase?
Alcohol group
Product of the fifth enzymatic step of fatty acid synthase?
alpha beta trans enoyl-ACP
Enzyme used in the fifth step of fatty acid synthase?
beta-hydroxyacyl-ACP dehydrase
Formula of product of fifth enzymatic step of fatty acid synthase?
CH3CHCHCO~S-ACP
Sixth step of fatty acid synthase?
Reduction (hydrogenation) of alpha beta trans enoyl-ACP
Which functional group is reduced in the sth step of fatty acid synthase?
Alkene
Product of the sixth step of fatty acid synthase?
acyl-ACP
Formula of product of sixth enzymatic step of fatty acid synthase?
CH3CH2CH2CO~S-ACP
Enzyme used in sixth step of fatty acid synthase?
enoyl-ACP reductase
What happens to the acyl part of the acyl-ACP group after the sixth step of fatty acid synthase?
Ity is transferred to the beta-ketoacyl synthase domain of the protein
Last 2C addition part of fatty acid synthase?
palmitoyl-ACP–> Palmitaie + ACP-SH
Enzyme catalysing final step of formation of palmitate?
palmitoyl thoesterase