User:Sarah Burkhard/Notebook/471 Nano Notebook/2017/03/08

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Objectives UV-Vis Arginine - Cysteine combination samples make capped Arg solution, ~ 50 mM use capped Arginine at pH 8 , 10 , and 14 use Arginine at pH 14 make new Arginine - Cysteine ratios Data Arginine pKa1 2.18 (carboxylic group will be protonated only at pH below 2.18 ) pKa2 9.09 (amine will be protonated only at pH values below 9.09 ) pKaR 13.2 (amine in R chain will be protonated at pH values below 13.2) charges: below 2.18: charge is 2+ 2.18 - 9.09: +1 9.09 - 13.2 : 0 above 13.2: -1 pI 10.76 (molecule will have a net charge of 0 ) Image of N-capped Arginine: Arg-Cys ratios We will keep the total concentration of amino acids constant: 3.125 mmolar 1:10 ratio Arg - Cys: 0.28 mM Arg | 2.84 mM Cys Volume ratio : 28.54 uL Arg | 282.13 uL Cys 1:5 ratio Arg - Cys: 0.52 mM Arg | 2.60 mM Cys Volume ratio : 52.32 uL Arg | 259.13 uL Cys Notes If the hypothesis is correct that a protonated amine is needed, NPs should form for all pH except above 13.2 . If the hypothesis is correct that the amino acid amine has to be protonated, NPs should not form above pH 9.09 . To test the latter , we will use capped Arginine , and see if it forms any nano particles. Lysozyme has 9 C and 11 R in its AA sequence. Myoglobin only had a couple ( 2 - 3) . Looking at Lysozyme data from last semester, we see that NPs are formed only pH 10.75 , in the presence of 0.75 mM fructose. pH 10 - 11 was measured in 0.25 increments. Peaks at 272 nm may indicate that gold 3+ remained in solution. That peak is strongest for pH 10 and 10.25.