Microcalorimetric study of the system adenosine-5′-triphosphate—sodium, potassium adenosine-5′-triphosphatase: Part 1. Determination of the catalytic activity of Na+, K+ ATPase

✍ Scribed by M.L. Antonelli; V. Carunchio; M. Luciani

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 551 KB
• Volume: 252
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(91)87191-9

✦ Synopsis

The catalytic activity of adenosine-5'-triphosphatase (5'-ATPase), activated by Na+ and K+ ions in the presence of Mg2+ ions, was determined by a direct method using batch microcalorimetry. The enzymatic hydrolysis of S'-ATP in Tris-HCI buffer was used without any auxiliary reaction. The rate of heat change associated with the enzymatic reaction, which could be related to the enzymatic activity of the Na +, K+ ATPase, gave rise to a linear correlation between the calorimetric output and the enzymatic activity. The method was successfully applied to real matrices, in particular to membranes of human erythrocytes, without particular pretreatment.