88.PYRUVATE DEHYDROGENASE REQUIRES ALL EXCEPT
A.VITAMIN B1
B.VITAMIN B6
C.LIPOIC ACID
D.PANTOTHENIC ACID
ANS:VIT B6
Lipoic acid (LA) is a prosthetic group, which is covalently attached to a specific lysine residue in the lipoyl domains of the of the pyruvate dehydrogenase (PDH) multienzyme complex. Lipoyl-lysine's function consists of two parts: one is allowing the reactant to access three different catalytic sites (swinging arm), and the other one is carrying the substrate.
Chemical properties
Lipoic acid is a sulphur-containing carboxylic acids. The two sulphur atoms are located in a five-membered ring in adjacent positions. In enzymes it is covalently attached to the epsilon-amino group of a lysine residue, where it provides substrate binding and mobility (swinging arm, range about 14Å). The five-membered hererocycle can open between the two S-atoms (dihydrolipoyllysine)
Pathways
The best-known enzyme, which depends on lipoic acid is the PDH (pyruvate dehydrogenase) complex, which forms part of the centre of aerobic metabolism: the citrate cycle. [KEGG PATHWAYS]
Pyruvate dehydrogenase requires:
Vitamin B1: Thiamine/TPP, transaldolase.
Vitamin B5: Pantothenic acid, CoA
Vitamin B2: Riboflavin, FADH2
Vitamin B3: Niacin, NAD+
A.VITAMIN B1
B.VITAMIN B6
C.LIPOIC ACID
D.PANTOTHENIC ACID
ANS:VIT B6
Lipoic acid (LA) is a prosthetic group, which is covalently attached to a specific lysine residue in the lipoyl domains of the of the pyruvate dehydrogenase (PDH) multienzyme complex. Lipoyl-lysine's function consists of two parts: one is allowing the reactant to access three different catalytic sites (swinging arm), and the other one is carrying the substrate.
Chemical properties
Lipoic acid is a sulphur-containing carboxylic acids. The two sulphur atoms are located in a five-membered ring in adjacent positions. In enzymes it is covalently attached to the epsilon-amino group of a lysine residue, where it provides substrate binding and mobility (swinging arm, range about 14Å). The five-membered hererocycle can open between the two S-atoms (dihydrolipoyllysine)
Pathways
The best-known enzyme, which depends on lipoic acid is the PDH (pyruvate dehydrogenase) complex, which forms part of the centre of aerobic metabolism: the citrate cycle. [KEGG PATHWAYS]
Pyruvate dehydrogenase requires:
Vitamin B1: Thiamine/TPP, transaldolase.
Vitamin B5: Pantothenic acid, CoA
Vitamin B2: Riboflavin, FADH2
Vitamin B3: Niacin, NAD+
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