Why Does the Fda Approve the Process and Product Together?

Homework #1

[1.3] Why does the FDA approve the process and product together?

Process has to be significantly considered in FDA approval because any changes in the manufacturing process can impact the safety and efficacy of a product. There have been several examples where a small process change result in the forming of toxic trace compound in the product and cause severe side effects, including death. Process has to be validated using Good Manufacturing Process (GMP) and it has to be consistent. Any changes applied to the process would require new clinical trials to test the safety and efficacy of the product (Shuler & Fikret, 2002).

[2.5] What are major sources of carbon, nitrogen, and phosphorus in industrial fermentations?

As described by Shuler and Fikret (2002), major carbon sources in industrial fermentations are molasses (sucrose), starch (glucose, dextrin), corn syrup, and waste sulfite liquor (glucose). Nitrogen sources are ammonia or the ammonium salts [NH4Cl, (NH4)2SO4, NH4NO3), proteins, peptides, and amino acids. Phosphorus can be obtained from inorganic phosphate salts (KH2PO4 and K2HPO4), and organic phosphate salts (glycerophosphates).

[2.9] Briefly describe the primary, secondary, tertiary, and quaternary structure of proteins. What could happen if you substituted a tyrosine for a cysteine in the active site? What might happen if the substitution occurred elsewhere?

Primary structure of the protein is the amino acid sequence. Stretches of polypeptide chain that form α helices and β sheets constitute the protein’s secondary structure. The full three-dimensional organization of a polypeptide chain the protein’s tertiary structure, and if a particular protein molecule is formed as a complex of more than one polypeptide chain, the complete structure is designated as the quaternary structure (Alberts et al., 2002).

Substitution of amino acids in the active site may result in mutations and changes of protein function. If the substitution occurred elsewhere (not in the active sites or binding sites), mutations are likely to have fewer consequences (Betts & Russel, 2003).

[2.11] Contrast the advantages and disadvantages of chemically defined and complex media.

Defined media contain specific amounts of pure chemical compounds with known chemical composition, while complex media contain natural compound whose chemical composition is not exactly known. Complex medium usually can provide the necessary growth factors, vitamins, hormones, and trace elements, often resulting in higher cell yields compared to the defined medium; it is also less expensive. Defined media, on the other hand, can generate more reproducible result. Recovery and purification of a product is also easier and cheaper in defined media (Shuler & Fikret, 2002).

[2.15] Give characteristic dimensions for each of these organisms: E. coli, Yeast (S. cerevisiae), Liver cell (hepatocyte), Plant cell.

• E. coli                : 0.7-1.4 μm diameter, 0.5-5 μm3 in volume
• Yeast                 : 3-6 μm diameter, 20-160 μm3 in volume
• Liver cell        : 50-100 μm diameter  
• Plant cell        : 10-100 μm in diameter

(Milo et al., 2010)

Additional problem:

6) What interactions drive protein folding? Rank them with respect to the magnitude of the stabilization (drop in free energy) they provide to the folded state relative to the unfolded state.

1. Hydrophobic interactions.
2. Electrostatic interactions
3. Hydrogen bonds
4. Van der Waals forces

(Brandt, 2011)

Reference

Betts, M. J. & Russell, R. B. (2003). Amino Acid Properties and Consequences of Substitutions, in Bioinformatics for Geneticists (eds M. R. Barnes and I. C. Gray). United Kingdom: John Wiley & Sons, Ltd. Available from: http://onlinelibrary.wiley.com/doi/10.1002/0470867302.ch14/summary