Abstract
Abstract 1. Silicotungstate inhibits DPNH oxidase, succinoxidase, and 32Pi-ATP exchange activity at relatively low concentrations (150 µg per mg of protein). The inhibition is reversed by bovine serum albumin. 2. When the concentrations of silicotungstate are increased (0.3 to 1.4 mg per mg of protein), DPNH oxidase activity appears which is insensitive to rotenone. Addition of serum albumin restores rotenone sensitivity. 3. Silicotungstate was shown to interact directly with DPNH dehydrogenase. The higher levels of silicotungstate convert both the particulate and soluble DPNH dehydrogenase but not succinate dehydrogenase into an oxidase enzyme.
Highlights
1 The abbreviations used are: F1, coupling factor 1 (ATPase); STA-particles, submitochondrial particles prepared by treatment of A-particles with 1% silicotungstate; A-particles, submitochondrial particles prepared from mitochondria exposed to sonic oscillation at an alkaline pH; SMP, submitochondrial particles prepared from heavy layer bovine mitochondria exposed to sonic oscillation in the presence of 10 mM sodium pyrophosphate, pH 7.4
The inhibition by rotenone depended both on the amount of serum albumin added as well as on the conditions of preparation of the STA-particles
Serum albumin added before rotenone stimulated the rate of oxidation slightly and the subsequent addition of rotenone inhibited completely
Summary
1. Silicotungstate inhibits DPNH oxidase, succinoxidase, and 32Pi-ATP exchange activity at relatively low concentrations (1.50 pg per mg of protein). The inhibition is reversed by bovine serum albumin. 2. When the concentrations of silicotungstate are increased (0.3 to 1.4 mg per mg of protein), DPNH oxidase activity appears which is insensitive to rotenone. Addition of serum albumin restores rotenone sensitivity
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
