1.) which protein is responsible for the contraction and relaxation of muscles ?

2.) what is the other name of involuntary and voluntary muscles ?

1. actin and myosin proteins help in contraction and relaxation of muscles.

2.Specifically there is no other name for voluntary and involuntary muscles but structurally muscles are divided into involuntary smooth muscles, voluntary striated muscles and involuntary cardiac muscles. So, striated muscles are voluntary muscles and both smooth and cardiac muscles are involuntary.