In: Biology
Design your own degradative pathway. You know the rules(organic mechanisms), and you've seen the kinds of reactions that occur in the biological degradation of fats and carbohydrates into acetyl CoA. If you were Mother nature, what series of steps would you use to degrade the amino acid serine into acetyl CoA? Need Help!!!
PLEASE BE DETAILED IN YOUR ANSWER. THANK YOU.
Serine is converted to pyruvate by serine dehydratase. Both the ?-hydroxyl and the ?-amino groups of serine are removed in this single PLP-dependent reaction. Glycine has two pathways. It can be converted into serine by enzymatic addition of a hydroxymethyl group. This reaction is catalyzed by serine hydroxymethyl transferase, it requires the coenzymes tetrahydrofolate and pyridoxal phosphate. The second pathway for glycine, which predominates in animals, It involves in oxidative cleavage into CO2, NH4+ and a methylene group (-CH2-).
This readily reversible reaction is catalyzed by glycine synthase. It also requires tetrahydrofolate, which accepts the methylene group. In this oxidative cleavage pathway the two carbon atoms of glycine do not enter the citric acid cycle. One is lost as CO2, and the other becomes the methylene group of N5,N10- methylene- tetrahydrofolate, which is used as a one-carbon group donor in certain biosynthetic pathways.
Tetrahydrofolate (H4 folate): This cofactor is synthesized in bacteria and its precursor, folate, is a vitamin for mammals. The one-carbon group, in any of three oxidation states, is bonded to N-5 or N-10 or to both. The most reduced form of the cofactor carries a methyl group, a more oxidized form carries a methylene group, and the most oxidized forms carry a methenyl, formyl, or formimino group. The different forms of tetrahydrofolate are interconvertible and serve as donors of one-carbon units in a variety of biosynthetic reactions. The major source of one-carbon units for tetrahydrofolate is the carbon removed in the conversion of serine to glycine, producing N5,N10-methylenetetrahydrofolate