Water structure in modified bovine plasma albumin (BPA) gel and bovine mercaptalbumin solution. 1H-n.m.r. studies.
Bovine plasma albumin Fr. V (BPA) has been known to contain small amounts of proteolytic enzyme. Wilson & Foster (1971) found a very limited and specific cleavage of BPA catalyzed by the enzyme with BPA in the F-form near pH 3.8, resulting in the formation of partially hydrolyzed BPA (BPA*). BPA* had a tendency to form a transparent gel at pD 4.0 (pD range of the F-form) above 8%, though proteolytic enzyme-free bovine mercaptalbumin (BMA) was in a transparent solution at pD 4.0 even at 12%. Water structures of the F-form of BMA in the solution state and of BPA* in the gel state were studied by measuring 1H-n.m.r. spectra, spin-lattice relaxation time (T1) and cross relaxation time (TIS) between irradiated and observed protons. Protein concentration-dependent changes of T1 of water protons indicated that the amount of hydrated water of BPA* in the gel state is far greater than that of the F-form of BMA in the solution state. TIS values from protein protons to water protons also indicated a large amount of hydration of BPA*, strong interaction between water and BPA* and rapid exchange between bound and bulk water in the gel state.
D000818:Animals; D002417:Cattle; D005782:Gels; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D011487:Protein Conformation; D012709:Serum Albumin; D012710:Serum Albumin, Bovine; D012996:Solutions; D014867:Water
D005782:Gels; D012709:Serum Albumin; D012996:Solutions; C001702:mercaptoalbumin; D014867:Water; D012710:Serum Albumin, Bovine