Final answer:
The defining characteristic of an enzyme in a sequential reaction is that all substrates must bind to the enzyme before any product release, forming a ternary complex. In contrast, a double-displacement reaction involves the release of a product before all substrates have bound, with a temporary modified enzyme intermediate formed in the process.
Step-by-step explanation:
Defining Characteristics of Enzymes in Sequential and Double-Displacement Reactions
The defining characteristic of an enzyme catalyzing a sequential reaction is that all substrate molecules must bind to the enzyme's active site before any product is released. This is in contrast to a double-displacement reaction (also known as a Ping-Pong reaction), where one or more products are released before all substrates have bound to the enzyme. Sequential reactions require the formation of a ternary complex involving the enzyme and all substrates, while in double-displacement reactions, a temporary modified form of the enzyme (an intermediate) is created after releasing a product before the second substrate binds.
Enzymes are highly specific biological catalysts that facilitate chemical reactions by lowering the activation energy. This specificity comes from the unique structural conformation of the active site, allowing only certain substrates to bind, akin to a lock and key mechanism. This contrasts with inorganic catalysts, which typically lack this level of specificity.
In terms of enzyme classification, it is largely based on the type of reaction catalyzed, which includes systematic enzyme names revealing both the substrate acted upon and the reaction catalyzed, such as in the case of alcohol dehydrogenase carrying out the oxidation of alcohols.