WATER VAPOR SORPTION OF BOVINE AND PORCINE SUBMAXILLARY MUCINS

Water vapor sorption isotherms were obtained on bovine and porcine submixillary mucin preparations. The reproducibility of the isotherms on porcine submixillary fractions indicated a definite denaturation process during each sorption-desorption cycle. This is interpreted as follows: The protein core of the porcine submaxillary mucin was accessible to water vapor. This was due to the uneven distribution of carbohydrate side chains on the protein core which left certain domains free of carbohydrate moieties. The bovine submaxillary mucin had high water sorption capacity and its isotherm showed a relatively good reproducibility. This indicates that the carbohydrate side chains were more evenly and densely distributed on the protein core of the bovine material than on the porcine material. The differences in sorptive capacities and retentive capacities are discussed. © 1968.