Protein is essential for life. It breaks down in amino Acids. This amino acids provides the building blocks for tissue, hormones, enzymes and accounts for 15% of the body.
You can calculate the intake of proteins very easily. According to The DRI (Dietary Reference Intake) one needs 0.8 grams of protein per kilogram of body weight.
For example if your body weight is 70 kgs then you need 70 X 0.8 = 56 grams of Proteins.
This amount of protein is to be taken gradually during the day instead of one go. Although, there is no evidence that a reasonably high protein intake has any adverse effects in healthy people trying to stay healthy.