Transferrin Rat Plasma. Transferrin (HOLO), Source: Rat Plasma, Physical Form Description: Lyophilized from 20 mM Na phosphate, pH 7.4 and 150 mM NaCI, Molecular Weight: 80.0 kDa, Purity: greater than or equal to 98%, Storage Temperature: -20C Synonyms: Transferrin, Siderophilin, Size: 1 mg