Several enzymes play critical roles in salvage pathways. These include: - Thymidine kinase: Involved in the phosphorylation of thymidine to thymidine monophosphate. - HGPRT: Catalyzes the formation of nucleotides from hypoxanthine and guanine. - Adenine phosphoribosyltransferase (APRT): Converts adenine to adenosine monophosphate. - Deoxycytidine kinase (dCK): Phosphorylates deoxycytidine to deoxycytidine monophosphate.