The enzymes, known as thioredoxin were chemically stable at temperatures up to 32 degrees Celsius (58 degrees Fahrenheit) higher than their modern counterparts. The enzymes, which were several billion years old, also show increased activity at lower pH levels—corresponding to greater acidity.
Using a technique called ancestral sequence reconstruction, Gaucher and Georgia Tech biology graduate student Zi-Ming Zhao reconstructed seven ancient thioredoxin enzymes from the three domains of life—archaea, bacteria and eukaryote—that date back between one and four billion years
