Substratsspektrum

Substratsspektrum is a concept used in biochemistry to describe the set of substrates that an enzyme, transporter, or catalytic system can recognize and convert under defined conditions. It characterizes the enzyme’s substrate specificity and catalytic scope. A narrow substratsspektrum means the enzyme accepts only a few chemically related substrates; a broad substratsspektrum indicates substrate promiscuity, where multiple substrates with varying structures can be processed.

Determination of the substratsspektrum typically involves screening a curated library of potential substrates or measuring steady‑state kinetic parameters (Km, Vmax, kcat) for a range of substrates. The catalytic efficiency, often expressed as kcat/Km, provides a quantitative measure of performance across substrates. The spectrum can be described qualitatively (narrow or broad) or quantitatively (number of substrates tested, average efficiency).

Several factors shape the substratsspektrum. Active-site geometry and amino acid composition determine which chemical functionalities are accommodated, while co-factors, solvent effects, and reaction conditions (pH, temperature, ionic strength) influence substrate compatibility. Stereochemistry is important, as many enzymes exhibit enantioselectivity and accept only one enantiomer. Enzyme promiscuity refers to broad substrates compatibility, whereas strict specificity yields a limited substrate set.

Applications of substratsspektrum analysis include guiding substrate design in biocatalysis, predicting drug metabolism and toxicology in pharmacology, and optimizing metabolic pathways in metabolic engineering. Understanding the spectrum helps assess enzyme utility, evolution, and potential for engineering to expand or refine substrate acceptance.