Question

enzymes are _ they can perform their job over and over.
describe what property of enzymes prevents them from interacting with specific substrates.

Explanation:

Enzymes are catalysts. Catalysts speed up chemical reactions without being consumed in the process, which is why they can perform their job over and over.
The property of enzymes that prevents them from interacting with specific substrates is their specificity. Enzymes have an active site that has a specific shape and chemical environment. Only substrates that match this active - site (in terms of shape, charge, and other chemical properties) can bind to the enzyme. This is often described by the "lock - and - key" or "induced - fit" models. In the lock - and - key model, the enzyme's active site is like a lock and the substrate is like a key. Only the correctly shaped key (substrate) can fit into the lock (active site). In the induced - fit model, the enzyme's active site can slightly change its shape to better accommodate the substrate, but there are still specific requirements for the substrate to bind.

Answer:

Enzymes are catalysts.
The property of enzymes that prevents them from interacting with specific substrates is their specificity.