What is the next step in the process after a substrate enters the active site of an enzyme?

The chemical reaction occurs.

New substances called products are formed.

The enzyme and the substrate bind to form the enzyme-substrate complex.

The enzyme and the products bind to form the enzyme-products complex.

The correct answer is "The enzyme and the substrate bind to form the enzyme-substrate complex".

The very first step in the process of product formation in the presence of enzyme is formation of enzyme substrate complex. As soon as a substrate enters the active site of an enzyme the functional groups present in the substrate interact with the functional groups of amino acids which are present in the active site of the enzyme. Their interaction leads to the formation of enzyme substrate complex which is simply an intermediate in the process of product formation. The fate of the enzyme substrate complex depends upon the affinity between enzyme and substrate. If affinity between them is strong, it eventually leads to the formation of product. But, if the affinity between both of them is less then they may dissociate from each other leading to the reverse reaction. Reverse reaction here means that rather than forming product they will dissociate into enzyme and substrate from which they originally started. Dissociation constant gives an idea of their affinity with each other. A low dissociation constant implies that their binding affinity is more.

After a substrate enters the active site of an enzyme it forms an enzyme substrate complex which allows for the reaction to continue at a lower energy state.