INFLUENCES OF PROTAMINE ON THE Na⁺, K⁺-DEPENDENT ATPase AND ON THE ACTIVE TRANSPORT PROCESSES OF POTASSIUM AND OFL-DOPA INTO BRAIN SLICES

Abstract

The influences of protarnine on Na6, K6-dependent ATPase and active transport processes of potassium and L-dopa into brain cortex slices of guinea pig were examined. Addition of protamiile to the soluble ATPase preparation extracted from brain inicrosomes resulted in the formation of a precipitate, Protamine slightly stimulated the activity of the Na+, K+-dependent ATI'ase in the soluble and microsolnal preparatioi~s from the guinea pig brain. However, pretreatment of the ATPase preparations with protatnine a t 37 "C or 45 "C resulted in a loss of Na+, K+-dependent ATPase activity, though the activity of Mg++-ATPase was not iinfluenced. These effects s f protamine on the Na+, K*-dependent ATPase were antagonized by the presence of cations.Active transport of potassium and of L-dopa into the slices was decreased by pretreatment of the slices with protamine in sucrose nnedium a t 37 "C. However, a t a low temperature or irr Ringer solutioll there was no remarkable effect. The role of Na' , K+-dependent ATPase in the active transport of potassium and of L-dopa is discussed on the basis of these results.

The Isolation of Skeletal Muscle Mitochondria Showing Tight Coupling, High Respiratory Indices, and Differential Adenosine Triphosphatase Activities*

“…The inclusion of albumin in the incubation medium converts these mitochondria from the open form to a closed system, one which is accessible only to the lipid-soluble DNP vehicle for ATPase activation. Yoshida et al (1965) and Machinist and Crane (1965) have shown a closing action of the polycation, protamine, which has been shown to combine with acidic phospholipids of mitochondria. A soluble protein has been obtained from mitochondria (Pullman and Monroy, 1963; Machinist and Crane, 1965) which was shown to combine with the mitochondrial ATPase to yield an ATPase-inhibitor complex which did not react with water but was capable of coupling oxidation to phosphorylation.…”