What aspect of enzymes allows them to facilitate reactions?

Enzymes facilitate reactions primarily due to their role as catalysts, which means they lower the activation energy required for a reaction to occur. This catalytic property enables enzymes to enhance the rate of biochemical reactions without being consumed or permanently altered in the process. The interaction between the enzyme and its substrate is crucial; enzymes have specific active sites that bind to substrates, forming an enzyme-substrate complex. This interaction stabilizes the transition state of the reaction, making it easier for the reaction to proceed.

The effectiveness of enzymes also stems from their highly specific nature, where they usually catalyze only one or a few closely related reactions. This specificity is dictated by the unique three-dimensional structure of each enzyme, which is essential for fitting with the substrate like a key fits into a lock.

In contrast, factors such as the ability to absorb heat or operate solely at high temperatures do not characterize how enzymes function generally. While temperature can influence enzyme activity, enzymes themselves are not defined by their heat absorption or required temperature conditions. Additionally, mass and molecular weight of the enzymes do not directly correlate with their ability to facilitate reactions; rather, it is the structure and chemical properties that are of primary importance.