First, form and repair human tissues.

Second, regulate physiological functions, various enzymes, hormones and antibodies.

Third, the supply of energy, in fact, this is not the main energy supply. Although 1g protein can supply 4kcal, it is not economical and has some shortcomings.

Fourth, it can make muscles move mechanically, and the objects are myosin and actin.

Participate in blood coagulation and regulate acid-base balance.

Sixth, its transport function is aimed at hemoglobin.