Dihydropteroate Synthase Inhibitor

Dihydropteroate Synthase Inhibitors are a class of antibiotics that work by inhibiting the enzyme dihydropteroate synthase. This enzyme is crucial in the synthesis of folic acid, which is necessary for the production of DNA and RNA in bacteria. By inhibiting this enzyme, these antibiotics prevent the bacteria from replicating and growing.

Mechanism of Action

Dihydropteroate synthase inhibitors work by binding to the active site of the enzyme dihydropteroate synthase. This prevents the enzyme from catalyzing the conversion of para-aminobenzoic acid (PABA) to dihydropteroate, a key step in the synthesis of folic acid. Without folic acid, the bacteria cannot synthesize DNA and RNA, and therefore cannot replicate.

Examples

One of the most well-known examples of a dihydropteroate synthase inhibitor is sulfamethoxazole, which is often used in combination with trimethoprim, a dihydrofolate reductase inhibitor. This combination is known as co-trimoxazole, and is used to treat a variety of bacterial infections.

Resistance

Resistance to dihydropteroate synthase inhibitors can occur through several mechanisms. One common mechanism is the acquisition of a resistant form of the enzyme that is not inhibited by the drug. Another mechanism is the increased production of PABA, which competes with the drug for binding to the enzyme.

Side Effects

Side effects of dihydropteroate synthase inhibitors can include nausea, vomiting, diarrhea, and skin rash. In rare cases, they can cause serious side effects such as Stevens-Johnson syndrome and toxic epidermal necrolysis.

See Also

• Antibiotic resistance
• Sulfonamides
• Trimethoprim/sulfamethoxazole