How about these papers and the link using sonication or pressure to maximize protein yield.
-High Molecular Weight Proteins of Trypanosoma cruzi Reduce Cross-Reaction with Leishmania spp. in Serological Diagnosis Tests. BioMed Research International Volume 2014, Article ID 365403
-The Isolation and Characterization of the High-Molecular-Weight Glycoprotein from Pig Colonic Mucus. Biochem. J. (1978) 173, 569-578