Compare and contrast the MEP and MVA pathways Consider thing

Compare and contrast the MEP and MVA pathways. Consider things such as what final products do they produce? What precursors do they use? where do they occur in the cell? 1pt

Solution

Ans a: Compare and contrast MEP and MVA pathways

It is well known that terpenoids are biosynthesized via two pathways in plants: the mevalonate (MVA) pathway in the cytosol and the methylerythritol phosphate (MEP) pathway in the plastids. The 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) is the rate-limiting enzyme of the MVA pathway, and mevinolin (MEV) is a highly specific inhibitor of HMGR . The 1-deoxy-D-xylulose 5-phosphate synthase (DXS) and 1-deoxy-D-xylulose 5-phosphate reductoisomerase (DXR) are the key enzymes of the MEP pathway, and fosmidomycin (FOS) is an inhibitor of DXR. The MVA pathway generally supplies precursors for production of sesquiterpenes, triterpenes, dolichol and brassinosteroids. The MEP pathway generally supplies precursors for the biosynthesis of diterpenoids, carotenoids, gibberellins and chlorophylls. Only the MEP pathway in most eubacteria is used to supply precursors for terpenoid biosynthesis, and only the MVA pathway in fungi and animals is used. In plants, however, both the MVA and MEP pathways are used for terpenoid production. Yet, the crosstalk between the two pathways in plants is still unclear. Some exchanges of IPP between the cytoplasm and plastids did appear to occur, although with low efficiency. Some evidence indicated that IPP exchanges were probably in both direction, whereas, the delivery of precursor from the plastids to the cytosol seemed to operate more readily

Ans b: Final products - terpenoid production

Ans c: Precursors do they use

The MVA pathway generally supplies precursors for production of sesquiterpenes, triterpenes, dolichol and brassinosteroids.

The MEP pathway generally supplies precursors for the biosynthesis of diterpenoids, carotenoids, gibberellins and chlorophylls. Only the MEP pathway in most eubacteria is used to supply precursors for terpenoid biosynthesis

Ans d: Where do they occur in the cell

MEP-Plastids and MVA-Cytosol