Physical and enzymatic properties of nucleotide-depleted beef heart mitochondrial adenosine triphosphatase

✍ Scribed by Garrett, Neil E. ;Penefsky, Harvey S.

• Publisher: Wiley (John Wiley & Sons)
• Year: 1975
• Tongue: English
• Weight: 535 KB
• Volume: 3
• Category: Article
• ISSN: 0091-7419
• DOI: 10.1002/jss.400030507

✦ Synopsis

Abstract

Tightly bound adenine nucleotides are removed from multiple binding sites on beef heart mitochondrial ATPase (F~1~) by chromatography on columns of Sephadex equilibrated with 50% glycerol. Release of nucleotides from the enzyme is associated with large decreases in sedimentation velocity (from 11.9 S to 8.4 S) which may be observed in concentrated solutions of polyols. Polyol‐induced conformational changes are reversed when the enzyme is returned to dilute buffers. The nucleotide‐depleted enzyme restores oxidative phosphorylation in F~1~ ‐deficient submitochondrial particles. Reconstitution of nucleotide‐depleted F~1~ with the ATP analog (adenylyl‐imidodiphosphate) (AMP‐PNP), almost 5 moles of AMP‐PNP per mole of enzyme, results in preparations with substantially inhibited ATPase activity which nevertheless restores oxidative phosphorylation and the ^32^Pi‐ATP exchange reaction in F~1~ ‐deficient submitochondrial particles. Incubation of the analog‐labeled enzyme with ATP and Mg^++^ results in partial displacement of the analog and a time‐dependent recovery of ATPase activity.