So, in important area of protein is denaturation of protein. All the proteins have typical three-dimensional structure and will show their physiological effect on biological functions of living organism. So, this area is called as native protein. This phenomenon is called as native protein. When on two proteins by applying some physical changes, so what we are going to exhibit on to the proteins physical changes. What are the physical changes we can apply not to the given molecule? What are the physical changes are by changing temperature or by increasing temperature? By increasing temperature or by changing by doing chemical changes. By doing physical changes or by doing chemical changes. What are the chemical changes means? Change in pH. Change in pH. Or by disturbing the bonds, hydrogen bonds in the protein. We can change the aspects of protein, how it is possible once again. The three-dimensional structure of protein and its physiological activity on functions of living organism is called as term used to explain the term native protein. So, here nativity of protein changes by changing physical and chemical changes. What are the physical changes? On to the native protein we are going to increase temperature or on to the native protein. We can change pH or we can do some disturbing into the hydrogen bonding onto that protein. By these things, uncoiling of protein takes place. What is uncoiling? So, this is called as spherical screw shape of protein. So, these screws will go open like this. So, it is converted into this phenomenon is called as uncoiling. So, uncoiling of protein takes place. Next, globules are going to open. So, by these two factors, the protein is going to loss protein can lose its activity. This phenomenon is called as denaturation of protein. Means, we are going to disturb native protein character by doing physical changes and chemical changes. When we are going to apply physical and chemical changes, uncoiling of protein takes place. Globules are going to open. By this mechanism, proteins can lose its activity. A simple example, while we are going to make an omelette, the white area of egg, white portion of egg, become stiffy. That means, the protein molecules of egg will be converted into white color. This is the best example by heating or by increasing the temperature. The native character of protein portion of egg will be disturbed. This is called as denaturation of protein. Similarly, curdling of milk. While milk converted into curd, the protein molecules of milk distribute to convert into curd. So, these two are the examples, stands for denaturation of proteins.