carboxylation

Examples of carboxylation in the following topics:

• Organic Acid Metabolism

  • The most commonly metabolized organic acids are the carboxylic acids, which are organic acids containing at least one carboxyl (-COOH) group.
  • The general formula of a carboxylic acid is R-COOH, where R is a monovalent functional group.
  • Many types of carboxylic acids can be metabolized by microbes, including:

• Vitamins and Amino Acids

  • Amino acids are biologically important organic compounds made from amine (-NH2) and carboxylic acid (-COOH) functional groups, along with a side-chain specific to each amino acid.
  • While in plants, 1-aminocyclopropane-1-carboxylic acid is a small disubstituted cyclic amino acid that is a key intermediate in the production of the plant hormone ethylene.

• The 3-Hydroxypropionate Cycle

  • Propionyl-CoA carboxylase is an enzyme that functions in the carboxylation of propionyl CoA.
  • The acetyl-CoA carboxylase utilized in this cycle is biotin-dependent as well and catalyzes the carboxylation of acetyl-CoA to malonyl-CoA.

• Pyruvic Acid and Metabolism

  • The carboxylate (COO−) anion of pyruvic acid.
  • The cycle is also known as the citric acid cycle or tri-carboxylic acid cycle, because citric acid is one of the intermediate compounds formed during the reactions.

• Siderophores

  • Siderophores are classified by which ligands they use to chelate the ferric iron, including the catecholates, hydroxamates, and carboxylates.
  • The majors groups of siderophores include the catecholates (phenolates), hydroxamates and carboxylates (e.g. derivatives of citric acid).

• Lipid Metabolism

  • They are made of a hydrocarbon chain of variable length that terminates with a carboxylic acid group (-COOH).
  • In brief, the oxidation of lipids proceeds as follows: two-carbon fragments are removed sequentially from the carboxyl end of the fatty acid after dehydrogenation, hydration, and oxidation to form a keto acid, which is then cleaved by thiolysis.
  • A fatty acid is a carboxylic acid with a long aliphatic tail that may be either saturated or unsaturated.

• Aerobic Hydrocarbon Oxidation

  • Microbes can utilize hydrocarbons via a stepwise oxidation of a hydrocarbon by oxygen produces water and, successively, an alcohol, an aldehyde or a ketone, a carboxylic acid, and then a peroxide.

• The Incorporation of Nonstandard Amino Acids

  • For example, the carboxylation of glutamate allows for better binding of calcium cations, and the hydroxylation of proline is critical for maintaining connective tissues.

• The Reverse TCA Cycle

  • These enzymes are unique to reverse TCA and are necessary for the reductive carboxylation to occur.

• Purifying Proteins by Affinity Tag

  • BCCP (Biotin Carboxyl Carrier Protein), a protein domain recognized by streptavidin