Will dissolved proteins pass through a 0.2 micron filter?
Many proteins will pass through a 0.2 micron filter. If the proteins aggregate or if they stick to the filter material because it is charged, they may not.

Barring the above, a 0.2 micron filter will allow proteins up to 200kd to pass through.  There are some proteins that are larger.

Editing with some source material.

Nice Presentation on Pore Sizes and Membranes Here

Graphic from that presentation: