Abstract
When baker''s yeast respires without added substrate its respiratory quotient is 0.85. No stored polysaccharide disappears during this respiration. The respiration is associated with an esterification of inorganic phosphate (QOP2 = -40). In the presence of 2,4-dinitrophenol (DNP) aerobically a fermentation of stored carbohydrate is set up and the respiration is changed to an oxidation of carbohydrate. The fermentation induced by DNP is not inhibited by 10-3 iodoacetate.