EFFECTS ON RESPIRATION AND GLYCOLYSIS 



623 



creatic lipase is stimulated at 8.5 mM. The ATPase of pea mitochondria is 

 also stimulated by dehydroacetate, phosphate splitting being increased 

 around 200% by 1 mM (Forti, 1957), which might be related to the un- 

 coupling action reported by MarreeiaZ. (1956). Catalase is inhibited weakly 

 (K^ = 22 jnM) by dehydroacetate compared with other organic acids (Liick, 

 1957). The enzymes responsible for the destruction of mitomycin in Strepto- 

 myces mycelia are not affected by 4.8 mM dehydroacetate (Gourevitch et 

 al., 1961). It is difficult to explain some of the actions on metabolism with 

 this limited amount of information. 



EFFECTS ON RESPIRATION AND GLYCOLYSIS 



The effects of dehydroacetate on the endogenous respiration of minces of 

 various rat tissues are shown in Fig. 3-1. Brain and kidney respiration is 

 progressively depressed but muscle is anomalous in that marked stimulation 

 is observed at high dehydroacetate concentrations, while liver is stimulated 



■3 -2 



LOG (DEHYDROACETATE) ( Ml 



Fig. 3-1. Effects of dehydroacetate on the respi- 

 ration of rat tissue minces measured over a period 

 of 2 hr. (From Seevers et al., 1950.) 



moderately at all concentrations used. Brain slices respond as do the minces, 

 but liver slices are unaffected by dehydroacetate up to 9.3 mM and are 

 then depressed at higher concentrations. Mudge (1951) found 10 mM dehy- 

 droacetate to depress rabbit kidney slice respiration 25%, which is similar 

 to the inhibition reported by Seevers et al. (1950) in rat kidney. The stim- 

 ulation of respiration in muscle and liver might result from metabolism 



