Metabolic Pathway: A metabolic pathway or biochemical pathway, is an orderly sequence of reactions within a cell that either breaks down large molecules or builds up larger compounds from smaller ones. These pathways can be linear or circular, and each step in a pathway has a specific enzyme acting upon it.
Pathways that build large compounds such as proteins, lipids, and other large molecules are called biosynthetic pathways and are anabolic. These larger molecules will have a higher energy count. Pathways that break down larger molecules into smaller ones with lower energy are called degradative pathways and are catabolic. All pathways have the following participants:
- Substrates: Molecules that can enter a reaction and be acted on.
- Intermediates: Compounds that are formed between the beginning and end of a pathway.
- Enzymes: Proteins that catalyze reactions (and speed them up.)
- Cofactors: Organic molecules or ions that assist enzymes by carrying atoms or electrons. Without these cofactors the enzymes they assist are inactive. See the explanation of coenzymes for organic molecule cofactors.
- Energy Carriers: ATP, which donates energy to many reactions.
- End Products: Compounds present at the end of a pathway.
This page created 01 Oct 2012 17:36
Last updated 30 Jan 2017 05:59