Reduce Draw Call for Sprite

I am working on side scrolling game so for that I want to define strategy for game objects.

I want to reduce draw call for game objects that are not in camera visibility either they are gone or not get turn to come in focus.

I have some working experience with AndEnginge in which I handle this situation in following manner.

        public void enable() {

	public void disable() {

I am pretty new to unity 2d game development so I want suggestion in this to improve performance of my game.

Also provide guidance for 3d objects if they come in same situation.

Unity cameras support what you want out-of-the box . It is called Frustum culling. (Objects that are not visible by the camera are not rendered = no draw calls)

Find out more in the documentation for camera . Look for the clip panes section.