Dmetabolismen

Dmetabolismen, or D-metabolism, refers to the set of biological processes that handle D-enantiomers of biomolecules. This contrasts with the more common L-enantiomers that dominate metabolism in many organisms. D-metabolism encompasses the uptake, transformation, and sometimes excretion of D-amino acids, D-sugars, and other D-configured compounds.

The enzymatic basis of D-metabolism is specialized. Key components include racemases or epimerases that interconvert D- and L- forms, and enzymes that selectively oxidize or deaminate D-amino acids, such as D-amino acid oxidases and related dehydrogenases. In nature, D-alanine and D-glutamate are particularly notable because they are incorporated into bacterial cell walls, where they influence cell-wall structure and turnover. Some microorganisms also degrade environmental D-amino acids as a nutrient source.

In humans and other animals, D-metabolism is less prominent but still important. D-amino acids such as D-serine and D-aspartate can play signaling roles in the nervous system and endocrine tissues, and their levels are regulated by enzymes like D-amino acid oxidase. The gut microbiota contributes to the pool of dietary D-amino acids, and imbalances in D-metabolism have been explored in relation to health and disease, though the field is complex and still developing.

Environmental and biotechnological aspects of D-metabolism include the microbial breakdown of chiral pollutants and the use of stereoselective enzymes in bioremediation and industrial synthesis. Research continues to elucidate the physiological roles of D-enantiomers and the full scope of enzymes that govern their fate.