I can't believe that I'm about to indulge you with this.
The high costs associated with the purification of rhGH and other biopharmaceuticals during the manufacturing process is well known to anyone who is even remotely familiar it.
The fact that you are willing to throw out matter-of-fact statements like "
People that keep insisting that GH is so expensive to manufacture, do not understand the industry. The actual cost of the machinery to initially start a factory is very expensive. But once you have the machinery, the cost is quite inexpensive." is proof that it is you who does not understand the industry. Either that or you are intentionally trying to obfuscate the issue because of an agenda.
That we are still having this ridiculous discussion is absurd. By now it should be perfectly clear to any thinking person that this cockamamie idea of so-called generic Chinese GH being readily available at an affordable price, is a fantasy. The black market Chinese GH sellers/manufactures are expert alchemists, but I assure you the only thing they're turning into gold is the cash from desperate and ignorant buyers. Keep the dream alive, Muscles96.
BioMed Research International
Volume 2013 (2013), Article ID 312709, 18 pages
Review Article
Preparative Purification of Recombinant Proteins: Current Status and Future Trends
Mayank Saraswat, Luca Musante, Alessandra Ravidá, Brian Shortt, Barry Byrne, and Harry Holthofer
Abstract
Advances in fermentation technologies have resulted in the production of increased yields of proteins of economic, biopharmaceutical, and medicinal importance. Consequently, there is an absolute requirement for the development of rapid, cost-effective methodologies which facilitate the purification of such products in the absence of contaminants, such as superfluous proteins and endotoxins. Here, we provide a comprehensive overview of a selection of key purification methodologies currently being applied in both academic and industrial settings and discuss how innovative and effective protocols such as aqueous two-phase partitioning, membrane chromatography, and high-performance tangential flow filtration may be applied independently of or in conjunction with more traditional protocols for downstream processing applications.
"...Furthermore, escalating demands for increased protein titres, primarily for economic reasons, have shifted the bottleneck step from production to purification, with downstream processes (inclusive of purification) representing between 45 and 92% of the total cost of manufacturing a recombinant protein [4, 5]. Hence, devising an efficient and economical purification strategy is a key challenge and one which is faced by industrial and, to a lesser extent, by academic laboratories."
Journal of Bioscience and Bioengineering
Volume 99, Issue 4, April 2005, Pages 303–310
Review
Solubilization and refolding of bacterial inclusion body proteins
Surinder Mohan Singh,
Amulya Kumar Pand
Inclusion bodies produced in Escherichia coli are composed of densely packed denatured protein molecules in the form of particles. Refolding of inclusion body proteins into bioactive forms is cumbersome, results in poor recovery and accounts for the major cost in production of recombinant proteins from E. coli. With new information available on the structure and function of protein aggregates in bacterial inclusion bodies, it has been possible to develop improved solubilization and refolding procedures for higher recovery of bioactive protein. Inclusion bodies are formed from partially folded protein intermediates and are composed of aggregates of mostly single types of polypeptide. This helps to isolate and purify the protein aggregates to homogeneity before solubilization and refolding. Proteins inside inclusion body aggregates have native-like secondary structures. It is assumed that restoration of this native-like secondary structure using mild solubilization conditions will help in improved recovery of bioactive protein in comparison to solubilization using a high concentration of chaotropic agent. Analysis of the dominant forces causing aggregation during inclusion body formation provides information to develop suitable mild solubilization procedures for inclusion body proteins. Refolding from such solubilized protein will be very high due to restoration of native-like secondary structure. Human growth hormone inclusion bodies were purified to homogeneity from
E. coli cells before solubilization and refolding. Pure inclusion bodies were solubilized at alkaline pH in the presence of 2 M urea solution. The solubilized proteins were refolded using a pulsatile renaturation process and subsequently purified using chromatographic procedures. More than 40% of the inclusion body proteins could be refolded back to the bioactive native conformation. Mild solubilization is thus the key for high recovery of bioactive protein from inclusion bodies.
The Journal of Biological Chemistry, 276, 46856-46863. December 14, 2001
High Pressure Refolding of Recombinant Human Growth Hormone from Insoluble Aggregates STRUCTURAL TRANSFORMATIONS, KINETIC BARRIERS, AND ENERGETICS*
Richard J. St. John, John F. Carpenter, Claude Balny, Theodore W. Randolph
"... Frequently, after extensive research, refolding yields remain too low to justify commercial product recovery with chemical refolding methods. In addition, low protein concentrations needed for acceptable refolding yields lead to large processing volumes and require large quantities of toxic, corrosive chaotropes, with high associated purchase and disposal costs."
