[2] ISOPRENOID SYNTHESIS: MEVALONATE PATHWAY AND MEP/DOXP PATHWAY

What enzyme catalyzes the conversion of HMG to MVA hence is conitered the rate limiting enzyme of MVA pathway?

3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CoA Reductase)

MVA is the best target for ______ drugs

statin drugs

Precursor for cholesterol, hence its production is blocked when statin drugs are administered

HMG-CoA

What are the compounds formed by 5-Pyrophosphomevalonate?

Isopentenyl pyrophosphate (IPP) and Dimethylallyl pyrophosphate (DMAPP)

How many carbons and hydrogens does IPP and DMAPP have

C₅H₈

IPP + DMAPP = ?

Geranyl pyrophosphate (C₁₀PP)

Geranyl pyrophosphate (C₁₀PP) is used to make?

monoterpenes (thymol and limonin)

Geranyl pyrophosphate + IPP = ?

Farnesyl pyrophosphate (C₁₅PP)

Farnesyl pyrophosphate (C₁₅PP) is used to make?

Sesquiterpenes (Quinines/Artemisin)

Farnesyl pyrophosphate + IPP = ?

Geranylgeranyl pyrophosphate (C₂₀PP)

Farnesyl pyrophosphate × 2 = ?

Squalenes (C₃₀PP) like steroids (cardiac glycosides), or triterpenes (saponins)

A product derived from Geranylgeranyl pyrophosphate (C₂₀PP) that is commonly found in the tail of chlorophyll pigments.

Phytol

Geranylgeranyl pyrophosphate × 2 = ?

Carotenoids (Carotene and Xanthophyll)

Multiple additions of IPP to Geranylgeranyl pyrophosphate

Polyterpins (Gutta/rubber)

Building blocks for Isoprenoids in MVA Pathway

5C units (IPP and DMAPP)

Precursor of MEP/DOXP Pathway

Pyruvate

Key enzymes in MEP/DOXP Pathway that is targetted by anti-malarial drugs?

Reductoisomerase

Why is it called MEP/DOXP Pathway?

Because of the conversion of 1-Deoxy-D-xylulose-5-phosphate (DOXP) to 2-methyl erythriol 4-phosphate pathway (MEP) by Reductoisomerase to produce IPP

Plants do both MEP in the ________ and MVA in the ________

plastids; cytosol

MEP/DOXP is found in humans/animals

False