The disintegration of yeast with dry ice and some properties of the extract

Abstract

A simple procedure for the disintegration of yeast cells, by which litre quantities of cell extract (approximately 11 per cent dry weight) may be obtained, is described. The fresh yeast cake is treated with dry ice in a high speed electric homogenizer after which it is left to thaw out at 0°. No addition of buffer has to be made, and the cell juice obtained after centrifugation of the resulting slurry appears to contain different subcellular particles and various enzymes in a relatively native state. When the extract is incubated at higher temperatures, proteolysis will rapidly change the electrophoretic and enzymatic properties, which indicates that procedures involving autolysis may be dangerous when information about the chemical composition of the native enzymes is desired.

Yeast Hexokinase. I. Preparation of the Pure Enzyme*

“…The first method consisted of homogenizing small pieces of Dry Ice in an electric homogenizer and then crumbling about 200 g of yeast cake into the Dry Ice. The mixture was homogenized for 5 min (van Hofsten and Tjeder, 1961). In the other procedures ether or toluene was cooled to -30°with Dry Ice prior to crumbling the yeast cake into the cooled mixture.…”

Estimation of the disruption in freeze‐pressed Accharomyces cerevisiae by an electronic particle counter

“…Such minor damages have been described earlier. 3,5 At T = 20 the reduction of counts by one pressing is greater than at lower threshold levels. There may be several reasons for this.…”