How specific is the matching between enzyme and substrate?

The matching between enzyme and substrate can vary in specificity. Most enzymes have absolute specificity in that they will only bind to a specific substrate that matches the characteristics of its active site. Other enzymes may exhibit lower specificity and bind to multiple substrates to catalyze a reaction. 

Enzymes exhibit four types of specificity: 

• Absolute specificity, in which an enzyme exclusively binds to one specific substrate and catalyzes only one reaction with that substrate
• Group specificity, in which an enzyme reacts only with molecules that contain specific functional groups such as methyls, phosphate groups, or aromatic structures
• Bond specificity, in which an enzyme recognizes only certain types of chemical bonds such as a peptide bond
• Stereochemical specificity, in which an enzyme recognizes a substrate’s optical activity of orientation