Transition state structure of the substrate formed during an enzymatic reaction is:
The correct option is D Temporary and unstable
The substrates bind with enzymes to form an intermediate enzyme-substrate complex (also known as transition state). This complex/state is highly unstable and temporary. The complex dissociates to form the products.
E (Enzyme) + S (Substrate) → ES (Enzyme-Substrate Complex) → E (Enzyme) + P (Product)