High yield electroextraction of proteins from yeast by a flow process

High yields of intracellular enzymes from yeast can be obtained by application of a series of electric field pulses with a flow process. Up to 80-90% of the total activity can be liberated without any further or previous treatment of cells. The method is based on electroinduced changes in the cell envelope leading to a leakage of part of the intracellular proteins without formation of debris and permits treatment of large volumes. Field parameters require a limited electrical power. Treatment of at least 20% wet weight suspensions is possible. The optimal field conditions must be adjusted to the suspension concentration. Maximal yield is obtained within 4 h at 30 degreesC for enzymes from Saccharomyces cerevisiae such as hexokinase, 3-phosphoglycerate kinase, and glyceraldehyde-3-phosphate dehydrogenase. The extraction of beta-D-galactosidase from Kluyveromyces lactis lasts 10 h but can be accelerated by adding dithiothreitol in the postpulse medium. The specific activities of the electroextracted enzymes are higher than those obtained by mechanical disintegration or enzymatic lysis. (C) 2003 Elsevier Science (USA). All rights reserved.