An HPLC-based fluorometric assay for serine hydroxymethyltransferase

Area of Science:

• Biochemistry
• Enzymology
• Analytical Chemistry

Background:

• Serine hydroxymethyltransferase (SHMT) is a key enzyme in folate metabolism, crucial for one-carbon unit transfer.
• Accurate quantification of SHMT activity is essential for understanding its role in various biological processes and diseases.
• Existing assays may have limitations in sensitivity, specificity, or throughput.

Purpose of the Study:

• To develop and validate a novel, sensitive, and reliable HPLC-based fluorometric assay for measuring serine hydroxymethyltransferase (SHMT) activity.
• To establish the performance characteristics of the assay, including its dynamic range and applicability.

Main Methods:

• A novel high-performance liquid chromatography (HPLC)-based fluorometric assay was developed.
• Serine hydroxymethyltransferase activity was assessed by quantifying the formation of 5,10-methylene-tetrahydrofolate (5,10-CH(2)-H(4)PteGlu).
• The intermediate was reduced to 5-methyl-tetrahydrofolate (5-CH(3)-H(4)PteGlu) using sodium borohydride (NaBH(4)) and subsequently quantified via reversed-phase HPLC with fluorescence detection.

Main Results:

• The assay demonstrated high sensitivity, capable of measuring SHMT activity over a concentration range of 10(-8) to 10(-3)M (6R,S)-tetrahydrofolate (H(4)PteGlu).
• The method provides accurate and reproducible quantification of 5-CH(3)-H(4)PteGlu, the fluorescent product.
• Separation of assay components was achieved under isocratic conditions, simplifying the chromatographic procedure.

Conclusions:

• A novel and robust HPLC-fluorometric assay for serine hydroxymethyltransferase activity has been successfully developed.
• This assay offers a sensitive and reliable method for quantifying SHMT activity, suitable for biochemical and clinical research.
• The established assay provides a valuable tool for further investigations into folate metabolism and related enzymatic studies.