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Sure, but It wouldn't be substituted 1 for 1. Just looked around quickly and found that soy protein concentrate is about 60% protein and the flour is about 40%.
There's a lot of people that use flours for binders including tapioca, rice, wheat and oat to name a few.
As said, soy protein concentrates work well. Different types might have different flavor profiles. Non fat dried skim milk powder can be used as well, but again will be slightly different.