coenzyme

Examples of coenzyme in the following topics:

• Cofactors and Energy Transitions

  • They can also be classified depending on how tightly they bind to an enzyme, with loosely-bound cofactors termed coenzymes and tightly-bound cofactors termed prosthetic groups.
  • Many contain the nucleotide adenosine monophosphate (AMP) as part of their structures, such as ATP, coenzyme A, FAD, and NAD+.
  • Vitamins can serve as precursors to many organic cofactors (e.g., vitamins B1, B2, B6, B12, niacin, folic acid) or as coenzymes themselves (e.g., vitamin C).
  • Many organic cofactors also contain a nucleotide, such as the electron carriers NAD and FAD, and coenzyme A, which carries acyl groups.
  • These group-transfer intermediates are the loosely-bound organic cofactors, often called coenzymes.

• Energy Conservation and Autotrophy in Archaea

  • Methanogenesis uses a range of coenzymes that are unique to these archaea, such as coenzyme M and methanofuran.

• Pyruvic Acid and Metabolism

  • Pyruvate is converted into acetyl-coenzyme A, which is the main input for a series of reactions known as the Krebs cycle.
  • Pyruvate from glycolysis is converted by fermentation to lactate using the enzyme lactate dehydrogenase and the coenzyme NADH in lactate fermentation.

• Types of Catabolism

  • Next, these smaller molecules are taken up by cells and converted to yet smaller molecules, usually the acetyl coenzyme A (acetyl-CoA), which releases some energy.
  • Finally, the acetyl group on the CoA is oxidized to water and carbon dioxide in the citric acid cycle and electron transport chain, releasing the energy that is stored by reducing the coenzyme nicotinamide adenine dinucleotide (NAD+) into NADH.
  • An alternative route for glucose breakdown is the pentose phosphate pathway, which reduces the coenzyme NADPH and produces pentose sugars such as ribose, the sugar component of nucleic acids.

• Methanogenesis

  • It involves the coenzymes and cofactors F420, coenzyme B, coenzyme M, methanofuran, and methanopterin.

• Citric Acid and Other Organic Compounds

  • It is produced from acetyl coenzyme A and oxaloacetate in the presence of the enzyme citrate synthase.

• Carboxysomes

  • Similar structures are known to harbor the B12-containing coenzyme glycerol dehydratase, the key enzyme of glycerol fermentation to 1,3-propanediol, in some Enterobacteriaceae, such as Salmonella.

• Habitats and Energy Metabolism of Crenarchaeota

  • Methanogenesis involves a range of coenzymes that are unique to these archaea, such as coenzyme M and methanofuran.

• The Incorporation of Nonstandard Amino Acids

  • A rare exception to the dominance of α-amino acids in biology is the β-amino acid beta alanine (3-aminopropanoic acid), which is used in plants and microorganisms in the synthesis of pantothenic acid (vitamin B5), a component of coenzyme A.

• The Reverse TCA Cycle

  • 5) succincyl CoA is converted to alpha-ketoglutarate via an alpha-ketoglutarate synthase (reduction of carbon dioxide occurs and oxidation of coenzyme A)