METABOLIC CONTROL OF STRUCTURAL STATES OF MITOCHONDRIA 9 1 



high concentrations of PCMB the initial shrinkage period is only 

 transient, but at low concentrations the high shrinkage state is maintained 

 for considerable time and reversal only occurs after long incubation times. 

 Similar findings have been observed with uncoupling agents. 



It is suggested that the period of shrinkage induced by PCMB and 

 uncoupling agents prior to swelling is the result of their ability to interact 

 with an enzyme of the coupling mechanism to augment adenosine triphos- 

 phatase activity recently reported by Cooper [27] through interaction with 

 inhibitory sulphydryl groups. However, after PCMB has been able to 

 bind sulphydryl groups more extensively a deformation of the macro- 

 molecular structure occurs which leads to severe swelling. Based upon the 



PCBM (83//M) 



Clutamate 

 3-hydroxybutyrate 



(/-ketoglutarate 



1 2 3 4 5 6 7 

 Time (min) 



Fig. 5. Effect of /)-chloromt'rcuribenzoate on the shrinking-swelling phenome- 

 non in cardiac muscle mitochondria. 



current concepts of myosin B-ATPase action, it is postulated that a protein 

 very similar to but difi^erent from the contractile muscle proteins will be 

 isolated from mitochondrial systems as was suggested 4-5 years ago by 

 Chappell and Perry [28]. 



References 



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2. Slater, ¥.. C, Aiist.J. exp. Biol. med. Set. 36, 51 (1958). 



3. Raaflaub, J., Helv. physiol. acta 1 1, 242 (1953). 



4. Brenner-Holzach, O., and Raaflaub, J., Helv. physiol. acta 12, 242 (1954). 



5. Lehninger, A. L.,_7. hiol. Clioii. 234, 2465 (1959). 



6. Lehninger, A. L., Ray, B. L., and .Schneider, M.,^. biophys. hiochem. Cytol. 5, 



97 (1959)- 



7. Packer, L., and Tappel, A. L,.,jf. biol. Client. 235, 525 (i960). 



8. Chance, B., and Williams, G. R.,^. biol. Cbem. 217, 383 (1955). 



9. Cleland, K. W. and Slater, E. C, Biochem. J. 53, 547 (1953). 



10. Chappell, J. B., and Greville, G. D., Nature, Lottd. 182, 813 (1958). 

 ri. Hunter, F. E., Jr., Levy, J. F., Fink, J., Schutz, B., Guerra, F., and Hurwitz, 

 A.,y. biol. Ghent. 234, 2176 (1959). 



