You would be far better off using 3/4 A/C Plywood then that junk.
It does not hold screws or nails, will wick up moisture from the floor, and has very little loading strength.
With 3/4 plywood and plywood shelves you could add 1 X 4" strips of wood to set the shelves on and add another piece across the front under the shelf to stop the shelf to stop it from sagging.
With Melamine shelving it will start to sag as soon as you set anything on it.
Lowes or HD can cut the plywood to size before you leave the store. I would prime and paint with enamel paint before assembling it.