What is the temperature that causes proteins to stop functioning?

Proteins generally begin to denature and lose their functional structure at temperatures around 40-60 degrees Celsius (104-140 degrees Fahrenheit), although this can vary depending on the specific protein and its environment. At higher temperatures, typically above 70 degrees Celsius (158 degrees Fahrenheit), most proteins will become irreversibly denatured and cease to function properly. This process disrupts the hydrogen bonds and hydrophobic interactions that maintain a protein's three-dimensional structure.