I assume u are familiar with protein structures so without wasting time i would love to tell u this...Tertiary proteins basically classifies proteins into Globular, Fibrous, and membraneous proteins. Globular are not soluble, they form colloids in water. You can refer them to be "semisoluble"...Fibrous Proteins are very soluble in water. Some of my course mates call them "crystaloids"...Membraneous proteins allow ions to pass through them...so not all tertiarty proteins are soluble in water...