CELL PERMEABILIZATION AS A TOOL FOR MEASUREMENT OF INTRACELLULAR ENZYME-ACTIVITY IN A FLOW-INJECTION SYSTEM

A novel approach to the determination of the intracellular enzyme activity in yeast cells was investigated. After permeabilization of the cell membrane, it is possible to determine the activity of NAD-dependent formate dehydrogenase from Candida boidinii based on stopped-flow injection techniques combined with fluorimetric detection. C. boidinii cells were made completely permeable with reference to formate dehydrogenase activity using the surfactant digitonin (0.5%, v/v) in combination with the non-ionic detergent Triton X-100 (0.5%, v/v). The analytical system was automated. A frequency of six analysis cycles per hour and a linear response of the signal in the range of 0.01-3.0 U ml-1 were achieved.