PROCESS FOR REDUCING THE NUCLEIC ACID CONTENT OF YEAST PROTEIN

摘要

This disclosure relates to a process for producing a yeast protein by treating the yeast medium with zinc at critical points in the process to protect the endogenous nuclease when the pH of the medium is raised during separation of the protein from the cell walls. The endogenous nuclease then is available to reduce the nucleic acid content of the protein during a subsequent incubation step. The yeast cells are ruptured by homogenization; extracted to remove the protein from the cells; and the cell wall debris separated by centrifugation. The soluble fraction is treated with alkali to enable the endogenous ribonuclease to degrade the nucleic acid. Specifically it has been found that adding zinc to the growing yeast, or to the cells before homogenization, or to the homogenate of cell walls and yeast protein before it is made highly alkaline will permit the endogenous nuclease of the yeast to degrade its own nucleic acid to tolerable levels.