A microtiter plate-based assay for phosphoenolpyruvate carboxylase

Area of Science:

• Biochemistry
• Enzymology
• Analytical Chemistry

Background:

• Phosphenolpyruvate carboxylase (PEPC) is a key enzyme in carbon fixation pathways.
• Accurate quantification of PEPC activity is crucial for understanding plant metabolism and C4 photosynthesis.
• Existing assays may lack sensitivity or are not amenable to high-throughput analysis.

Purpose of the Study:

• To develop and validate a sensitive, quantitative microtiter plate-based assay for phosphenolpyruvate carboxylase (PEPC).
• To demonstrate the utility of the assay for analyzing enzyme activity in complex biological mixtures.

Main Methods:

• A colorimetric assay was developed utilizing the reaction of oxaloacetate (a product of PEPC activity) with Fast Violet B dye.
• The assay was optimized for microtiter plate format, enabling sensitive detection.
• The assay's applicability was tested by monitoring PEPC activity in fractions from size-exclusion chromatography of crude maize extract.

Main Results:

• The described assay provides sensitive and quantitative measurement of PEPC activity.
• The colorimetric reaction with Fast Violet B dye allows for straightforward detection.
• The assay successfully detected PEPC in separated fractions of maize extract, confirming its utility for chromatographic eluate monitoring.

Conclusions:

• A robust and sensitive microtiter plate assay for PEPC has been established.
• This assay is well-suited for the quantitative analysis of PEPC in chromatographic eluates.
• The method facilitates biochemical studies of PEPC and related metabolic pathways.