Some of the drugs used to treat HIV patients are competitive inhibitors of the HIV reverse transcriptase enzyme. Unfortunately, the high mutation rate of HIV means that the virus rapidly acquires mutations with amino acid changes that make them resistant to these competitive inhibitors. Where in the reverse transcriptase enzyme would such amino acid changes most likely occur in drug-resistant viruses?
A) in or near the active site
B) at an allosteric site
C) at a cofactor binding site
D) in regions of the protein that determine packaging into the virus capsid
E) such mutations could occur anywhere with equal probability
The rate of turnover in a metabolic pathway, otherwise known as the metabolic flux , is regulated based on the stoichiometric reaction model, the utilization rate of metabolites, and the translocation pace of molecules across the lipid bilayer .  The regulation methods are based on experiments involving 13C-labeling , which is then analyzed by Nuclear Magnetic Resonance (NMR) or gas chromatography-mass spectrometry (GC-MS) -derived mass compositions. The aforementioned techniques synthesize a statistical interpretation of mass distribution in proteinogenic amino acids to the catalytic activities of enzymes in a cell.