Lecture Notes on Terpenoids and Biosynthetic Pathways

Focus on terpenoids, a group of natural products.
Reading materials include "Organic Chemistry of Biological Pathways" by McMurry and Mann.
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Introduction to biosynthetic pathways in living organisms, emphasizing that they vary across species.
Key Term: Biosynthesis - Nature's method of forming molecules (natural organic synthesis).
Breakdown metabolism (catabolism) vs. building up metabolism (anabolism).
- Catabolism: Breaking down materials to generate energy and building blocks.
- Anabolism: Using building blocks to synthesize essential molecules.

Metabolism: Sum of all biochemical reactions in an organism.
Metabolites: Products formed as a result of metabolism (e.g., terpenes, alkaloids, non-ribosomal peptides).
Distinction between Primary Metabolites (essential for survival) and Secondary Metabolites (not essential, often for survival advantage):
- Primary Metabolites: Carbohydrates, proteins, nucleic acids, lipids.
- Secondary Metabolites: Defense compounds and compounds aiding survival, produced by specific organisms.

Often have significant biological effects and serve roles in competition among organisms (e.g., attracting pollinators, deterring competitors).
Produced in specific tissues or at certain times in the organism's life cycle.

Terpenoids represent the largest class of secondary metabolites (over 60,000 identified).
Importance in pharmaceuticals (e.g., steroids, Taxol, artemisinin).
History: Otto Wallach identified terpenoids, deriving their name from turpentine, originally classified by carbon count (C10, C20).

Lanosterol: Precursor for steroids, part of biosynthetic pathways related to hormones and medicinal compounds.
Paclitaxel (Taxol): An anti-cancer drug sourced from yew trees, significant in treating breast cancer.
Artemisinin: An essential anti-malarial compound, highlighting the importance of bioengineering for effective production.

Metabolism's complexity allows for bioengineering interventions to optimize production pathways for specific compounds.
Biosynthetic pathways can be tweaked to optimize the synthesis of high-demand metabolites.
Example with L-valine illustrates feedback mechanisms and gene regulation in metabolic pathways affecting final product yield.

Prokaryotes (e.g., Bacteria):
- Simpler structure, easier to manipulate.
- Growth potential without limits; used widely in genetic engineering (e.g., E. coli).
Eukaryotes (e.g., Yeast, Plant Cells):
- Complex organelles (e.g., mitochondria, endoplasmic reticulum) facilitating advanced biosynthetic reactions.
- Yeasts preferred for specific reactions needing more complicated biosynthetic machinery compared to bacteria.
Considerations in choosing cell types for biosynthetic processes based on metabolic requirements.

Importance of enzymes and co-factors (e.g., Coenzyme A, vitamins) in metabolic pathways.
Discussion of the pyruvate dehydrogenase complex and its role in converting pyruvate to acetyl-CoA.
Relationship of these processes to primary metabolism and the synthesis of important metabolites.

Key takeaways about the complexities of terpenoid biosynthesis, the importance of metabolic engineering, and the interdependencies in biosynthetic pathways.
Encouragement for further engagement with the topic in upcoming lectures, particularly regarding the detailed mechanisms of terpenoid synthesis.