Browning hydrophobic amino acids

Figure 5 Consequences of point mutations in D1 (yellow) and CP43 (green). In the boxes, the first line (-E) indicates amino acids mutations that support photoautotrophic growth (light-E COp) and evolve Op. The second line (Op) indicates mutants that do not grow photoautotrophically but retain an initial Op evolution rate when grown heterotrophically (>5% vs. the wild-type strain). The third line (—) indicates lethal mutants that do not grow photoautotrophically, have no Op evolution activity, and in some cases no photooxidizable Mn. Amino acid color coding acidic (red), basic (blue), hydrophobic (brown)...

Encapsulation and delivery of DNA has also been investigated with poly(amino acid) (poly(AA)) based polymer vesicles. Brown and coworkers synthesized an amphiphilic triblock copolymer from methoxy-poly(ethylene glycol) (mPEG), hydrophobic palmitic acid chains in block segments along a poly-L-lysine (PLL) or... 

Another assay, the Bradford assay, also known as the Coomassie dye binding method, was first described in 1976 [19]. In an acidic environment, proteins will bind to Coomassie dye and cause a shift from the reddish brown color (465 nm) to the blue dye protein complex read at 595 nm. The development of the color is attributed to the presence of the basic amino acids arginine, lysine, and histidine. Van der Waals forces and hydrophobic interactions account for the dye binding and the number of Coomassie blue dye molecules bound is roughly proportional to the number of positive charges on the molecule. A protein molecular weight of about 3 kDA is required for successful color development. The Bradford assay dose response is nonlinear and this method demonstrates the greatest difference in reactivity with BSA compared to BGG. 

Fig. 3.10. MOLCAD-predicted CB2-binding pocket surrounded by active amino acid residues, showing an amphipathic contour, hydrophilic center (blue), and hydrophobic cleft (brown). The site-directed mutagenesis-...

Amadori compounds (N-substituted-l-amino-l-deoxy-2-ketoses) are potential precursors to the formation of many of these heterocyclic volatile products. The secondary nitrogen in most Amadori compounds is weakly basic and is therefore a likely site for rapid nitrosation reactions via normal reactions with nitrous acid, under mildly acidic conditions. However, purified Amadori compounds are usually obtained only after tedious isolation procedures are invoked to separate them from the complex mixtures of typical Maillard browning systems. Takeoka et al. ( 5) reported high performance liquid chromatographic (HPLC) procedures to separate Amadori compounds in highly purified form on a wide variety of columns, both of hydrophilic and hydrophobic nature. They were able to thus demonstrate that reaction products could be followed for kinetic measurements as well as to ensure purity of isolated products. 

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