Which of the following is not the component of Multien- zyme Fatty Acid Synthase Complex?
Ans. d (Monoamine oxidase) (Ref. Harper's biochemistry 27th ed., Chapter 23)FATTY ACID SYNTHASE COMPLEX IS A POLYPEPTIDE CONTAINING 7 ENZYME ACTIVITIES# In mammals, the fatty acid synthase complex is a dimer comprising two identical monomers, each containing all seven enzyme activities of fatty acid synthase on one polypeptide chain.# Initially, a priming molecule of acetyl-CoA combines with a cysteine - SH group catalyzed by acetyl transacylase.# Malonyl-CoA combines with the adjacent - SH on the 4'-phosphopantetheine of ACP of the other monomer, catalyzed by malonyl transacylase (reaction 1b), to form acetyl (acyl)-malonyl enzyme.# It is liberated from the enzyme complex by the activity of a seventh enzyme in the complex, thioesterase (deacylase).# The free palmitate must be activated to acyl-CoA before it can proceed via any other metabolic pathway. Its usual fate is esterification into acylglycerols, chain elongation or desaturation, or esterification to cholesteryl ester. In breast, there is a separate thioesterase specific for acyl residues of C8, C,10, or C12, which are subsequently found in milk lipids.Educational Points:RATE-DETERMINING ENZYMES OF METABOLIC PROCESSESProcessEnzymeDe novo pyrimidine synthesisAspartate transcarbamylase (ATCase)De novo purine synthesisGlutamine-PRPP amidotransferaseGlycolysisPhosphofructokinase-1 (PFK-1)GluconeogenesisPyruvate carboxylaseTCA cycleIsocitrate dehydrogenaseGlycogen synthesisGlycogen synthaseGlycogenolysisGlycogen phosphorylaseHMP shuntGlucose-6-phosphate dehydrogenase (G6PD)Fatty acid synthesisAcetyl-CoA carboxylase (ACC)Fatty acid oxidationCarnitine acyltransferase 1KetogenesisHMG-CoA synthaseCholesterol synthesisHMG-CoA reductaseHeme synthesisALA synthaseUrea cycleCarbamoyl phosphate synthase 1
Acetyl transacylase
Enoyl reductase
Malonyl transacylase
Monoamine oxidase
Lipids