Isolation and characterization of murine lactoferrin

Area of Science:

• Biochemistry
• Proteomics

Background:

• Lactoferrin is an iron-binding glycoprotein found in mammalian milk.
• Understanding its properties is crucial for various biological and medical applications.

Purpose of the Study:

• To isolate and characterize lactoferrin from mouse milk.
• To determine its purity, molecular weight, and immunological characteristics.

Main Methods:

• Isolation via centrifugation, ammonium sulfate precipitation, and carboxymethyl-Sephadex chromatography.
• Purity and molecular weight assessed by polyacrylamide gel electrophoresis (PAGE) and sodium dodecyl sulfate (SDS-PAGE).
• Oligomeric forms investigated using sedimentation equilibrium ultracentrifugation.

Main Results:

• Highly purified lactoferrin was obtained, with lysine as the sole N-terminal amino acid.
• SDS-PAGE indicated a molecular weight of 78,000 ± 2800 Da; ultracentrifugation revealed monomers and oligomers.
• Isoelectric focusing showed a pI of approximately 9 (range 8.7-9.6).
• Immunodiffusion and immunoelectrophoresis confirmed a single precipitin line with anti-mouse lactoferrin, and no cross-reactivity with transferrin.

Conclusions:

• Mouse milk lactoferrin is a well-defined protein with specific physicochemical and immunological properties.
• The characterization provides a basis for further functional studies of mouse lactoferrin.