FORT COLLINS, Colo.--(BUSINESS WIRE)--

Optiferrin, a recombinant human transferrin (rhTF) protein produced by Ventria Bioscience using ExpressTec, has been shown to be biochemically and structurally similar to human transferrin (hTF) molecules derived either from human serum or a recombinant mammalian expression system, according to a paper published today in the Journal of Inorganic Biochemistry.1 Optiferrin is sold commercially by InVitria, the bioreagents division of Ventria Bioscience, for use in cell culture applications.

Recombinant human transferrin used in cell culture media supplements is available from a number of commercial sources, but characterization of these products rarely goes beyond a crude assessment of purity by gel electrophoresis, said Dr. Anne B. Mason, Research Professor of Biochemistry at the University of Vermont (Burlington, Vt.) and the senior author on the study. Functional validation by more thorough and quantitative methods such as ours is essential for either analytical purposes or for pharmaceutical development.

The paper, titled Biochemical and Structural Characterization of Recombinant Human Serum Transferrin from Rice (Oryza sativa L.), was the result of a collaboration between researchers at the University of Vermont College of Medicines Department of Biochemistry; the University of Massachusetts at Amhersts Department of Chemistry, (Amherst, Mass.); Ventria Bioscience; and InVitria. The research team used a battery of biochemical and biophysical techniques to compare the functional properties of Optiferrin to either native hTF purified from human serum, or a reference form of recombinant N-His-tagged nonglycosylated human transferrin (referred to as N-His hTF). As authorities on the biochemical properties of proteins involved in iron metabolism, Dr. Masons group had previously developed and characterized the mammalian expression system used to produce the N-His hTF protein and mutant variations and also developed many of the biophysical techniques used in this study as part of their ongoing research.

The in-depth biochemical and structural characterization analysis included techniques such as peptide mapping and capillary liquid chromatography with tandem mass spectrometry; circular dichroism spectrometry; ultraviolet-visible (UV-vis) spectroscopy; determination of molar absorption coefficient for iron; steady-state tryptophan fluorescence; relative transferrin-receptor binding affinity; and iron release under simulated endosomal conditions. The results demonstrated that Optiferrin is biochemically and structurally similar to hTF, exhibiting the tight but reversible binding to iron (Fe3+) that is a hallmark of transferrin function.

Human transferrin, either purified from human blood serum or biomanufactured using various recombinant protein expression systems, is widely used in biomedical research and the biotechnology industry as a supplement to support mammalian cell growth in serum-free cell culture media. It also has potential therapeutic uses in the treatment of thalassemia, atransferrinemia, and age-related macular degeneration, and as an anti-cancer drug delivery molecule. However, hTF sourced from serum poses the risk of transmission of blood-borne pathogens, while current systems for recombinant expression are difficult to scale in a cost-effective manner for biopharmaceutical applications. Thus a cost-efficient production method is desirable. The authors of the present study performed a basic economic analysis of current rhTF biomanufacturing methods (Table S1) and found that rhTF produced using Ventria Biosciences ExpressTec technology is dramatically more cost effective than other commercial methods, including yeast, immortalized human cell lines (HEK293), or wheat germ.

While we have long known that Optiferrin supports optimal cell growth in serum-free media, this study provides further validation that recombinant human transferrin produced using our ExpressTec technology functions similarly to its endogenous counterpart, said Scott Deeter, president and CEO of Ventria Bioscience. These results will support our future efforts toward developing a cost-effective, biopharmaceutical-grade human transferrin product.

1 Full citation: Steere AN, Bobst CE, Zhang D, Pettit S, Kaltashov IA, Huang N, Mason AB. Biochemical and structural characterization of recombinant human serum transferrin from rice (Oryza sativa L.). J Inorg Biochem. 2012;116:37-44. doi: 10.1016/j.jinorgbio.2012.07.005.

About InVitria

InVitria develops, manufactures and markets a portfolio of animal-free cell culture supplements that improve performance, cost effectiveness and consistency of cell-based biomanufacturing systems. InVitria is a division of Ventria Bioscience. For more information, visit http://www.invitria.com.

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Study Shows Optiferrin™ Recombinant Human Transferrin Is Comparable to Serum-Derived or Mammalian-Expressed Transferrin