The Metabolic Pathway ofShikimic Acid Aromatic Amino AcidsPhenolic Compounds Jan Michael O. Santos Philippine Normal University College of Science Department of Physical Sciences
Outline of Discussion 1. Shikimic Acid Pathway • Origin of Shikimic Acid • Starting Material • Enzymes • Pathway- Mechanism • Product
2. Aromatic Amino Acids • What are the Aromatic Amino Acids • Starting Material • Enzymes • Pathway- Mechanism • Products
3. Phenolic Compounds • What are Phenolic Compounds • Starting Material • Enzymes • Pathway- Mechanism • Products
DEFINITION OF TERMS • Shikimic acid or shikimate: is an important biochemical metabolite in plants and microorganisms. • Aromatic compound: is a hydrocarbon with alternating double bonds and single bonds between carbon atoms • Amino acids: are molecules containing an amine group, a carboxylic acid group and a side chain (specific)
4. Phenolic Compounds: are a large and diverse group of molecules, which includes many families of aromatic secondary metabolite in plants. 5. Enzymes: are group of molecules that serve as a catalyst with a high degree of specificity for a certain substrate or class of substrates. It can only act on one substrate or on a family of structurally similar substrates.
MAJOR ENZYMES • Synthase: Joints two molecules together w/o hydrolyzing a pyrophosphate bond. • Dehydratase: Removes water to create a double bond • Dehydrogenase: Removes hydrogen atom from its substrate • Kinase: Transfer a phosphate group from a high-energy phosphate compound such as ATP to its substrate.
Where this came from? Shikimi Illiciumanisatum
Shikimic acid is a precursor for: • Aromatic amino acids phenylalanine and tyrosine • Indole, and indole derivatives and a.a.a tryptophan • Alkaloids • Phenylpropanoids, flavonoids, tannins, and lignins.
FORMATION OF SHIKIMIC ACID Starting materials 1st: Pyruvate to Phospoenolpyruvate
FORMATION OF SHIKIMIC ACID 2nd : Erthryrose-4-phosphate
FORMATION OF SHIKIMIC ACID Analyze this reaction, what are the other materials involve?
FORMATION OF SHIKIMIC ACID 3-deoxy-D-arabinoheptulosonate 7-phosphate (DAHP) synthase is the first enzyme in a series of metabolic reactions known as the shikimate pathway. Since it is the first enzyme in the shikimate pathway, it controls the amount of carbon entering the pathway.
FORMATION OF SHIKIMIC ACID phosphoenolpyruvate B: H+ erythrose-4-phosphate H+ H+ NADPH shikimic acid
FORMATION OF SHIKIMIC ACID 3-dehydroquinate synthaseis the second enzyme of the shikimate pathway. It catalyzes the elimination of phosphate from DAHP to generate 3-dehydroquinate (DHQ).
FORMATION OF SHIKIMIC ACID 3-Dehydroquinate Dehydratase (DHQD) catalyzes the third step of the shikimate pathway, dehydration of 3-dehydroquinate to 3-dehydroshikimate.
FORMATION OF SHIKIMIC ACID Shikimate-5-Dehydrogenase (SDH) The fourth step of the shikimate pathway is the reduction of DHS to shikimate. the reaction is catalyzed by an NADP-dependent shikimatedehydrogenase (SHD)
FORMATION OF SHIKIMIC ACID ShikimateKinase (SK)- In the fifth step of the shikimate pathway, shikimatekinase catalyzes the specific phosphorylation of the 3-hydroxyl group of D-shikimate to yield shikimate 3-phosphate using ATP as a co-subtrate
FORMATION OF SHIKIMIC ACID 5-Enolpyruvylshikimate 3-Phosphate Synthase (EPSPS) is the sixth enzyme of the shikimate pathway. It catalyzes the reversible formation of 5-enolpyruvyl-shikimate-3- phosphate (EPSP) from shikimate 3-phosphate and PEP.
FORMATION OF SHIKIMIC ACID ChorismateSynthase (CS) The seventh and final step in the main trunk of the shikimate pathway is the trans-1,4 elimination of phosphate from EPSP to yield chorismate
FORMATION OF SHIKIMIC ACID In this reaction, the second of the three double bonds of the benzene ring is introduced. The reaction is catalyzed by chorismatesynthase and requires reduced flavin for activity even though the overall reaction is redox neutral.
SHIKIMIC ACID TO AROMATIC ACID The seven-step shikimate pathway links the metabolism of carbohydrates to the biosynthesis of aromatic amino acids and many aromatic secondary metabolites, including tetrahydrofolate and ubiquinone.
Aromatic Amino Acids Y F W
Aromatic Amino Acids 1. What are aromatic amino acids? Aromatic Amino Acids are amino acids that include an aromatic ring. Example includes: Phenylalanine, Tryptophan, Histidine, Tyrosine (but only F, W, Y can be synthesized by Shikimate pathway)
The Aromatic Family • In plants and microorganism: Phe, Tyr, and Trp • Precursors are: • PEP • ERYTHROSE-4-PHOSPHATE • CHORISMATE
The Starting Material CHORISMATE
Enzymes Isomerase is an enzyme that catalyzes the structural rearrangement of isomers. Mutase: catalyzes the shifting of a functional group from one position to another within the same molecule. Transferase: catalyzes the transfer of a functional group (methyl or phosphate)from one molecule to another
The Mechanisms From Chorismate to Prephenate Chorismatemutase catalyzes the Claisen rearrangement of chorismate ion to prephenate ion
The Mechanisms What is Claisen Rearrangement? • Claisen Rearrangement is a powerful carbon-carbon bond-forming chemical reaction discovered by Rainer Ludwig Claisen.
OVER-ALL STRUCTURE CHORISMATE PREPHENATE