MAGNETIZATION-TRANSFER IN PROTEIN SOLUTIONS AT 0.1 T - DEPENDENCE ON CONCENTRATION, MOLECULAR-WEIGHT, AND STRUCTURE

Rationale and Objectives. We observed the magnetization transfer rates in a variety of protein solutions at 0.1-T magnetic field and compare d our results with previous investigations at high magnetic fields (>0 .5 T). The effects of protein concentration, size, pH, denaturation, c ross linking, and fiber formation were investigated. Methods. We used the saturation transfer technique to determine the transfer of magneti zation in gamma globulin, fibronectin, collagen, fibrinogen, and album in solutions. Results. The observed transfer rate increased with incre asing concentration and size of the protein. Protein degradation decre ased the transfer rate. Cross linking and fiber formation each increas ed the transfer rate, whereas buffer pH had no effect. Conclusion. Pro tein denaturation, aggregation, and fiber formation are important dete rminants of magnetization transfer in vitro. The size, concentration, and cross linking of the proteins contribute strongly to the transfer of magnetization at low fields, and the effect seems to be at least as important as at the higher fields.