Strong emotions trigger the nervous system, which can interfere with your ability to achieve sexual

Strong emotions trigger the Sympathetic nervous system, which can interfere with your ability to achieve sexual Arousal.

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products