Duta A Report Sheet Milk and Albumin from Egg White Record your observations reg
ID: 1058496 • Letter: D
Question
Duta A Report Sheet Milk and Albumin from Egg White Record your observations regarding clumping of proteins and whether the clumps settle quickly to the bottom the tube or remain suspended in the tube for a long time. You should also indicate whether the solution (especially egg white solution, which is clear to begin) becomes cloudy white aggregates) or whether there are large aggregates or clumps. Vinegar Mercuric Chloride Lead Nitrate Precipitation m mt Egg white no Preci Pl tation milk colon. eag white no Precis at on Boiling Water Bath Perchloric Acid Ethyl Alcohol No clu uping Egg white EEgg white Cloudy pweapritat while one. Cib, tition phe cipitation, m, lt. A-1. How do you explain any differences between the behavior ofegg albumin and casein with respect to precipitation by vinegar and precipitation by heating in boiling water? Think about what happens when you place an egg in boiling water or when milk is heated.Explanation / Answer
A-1 Egg albimin and casein are sensitive to addiiton of vinegar and acid and boiling water condition. In both the cases the denaturation of proteins occur present in egg albumin and casein. Thus precipitation occurred by denaturation in these cases.
B-1The test sample showed no color change as the pH is close to isoelectronic point and no change in the strcture is observed under these conditions.
C-1 Biuret test is a test for the presence of protein in the sample. When biuret reagent is added to the sample, formation of a ciolet color as seen in case of egg white confrms the presence of protein in the sample. The other milk solution gave postive tes but the rest did not give a positive test with the added reagent.
D-1 Millon's test for phenol is mercury metal in nitric acid in diluted form. It reacts with phenolic -OH group. Appearence of a reddish precipitate confirms phenol group as in tyrosine is present.
D-2 : Most of the proteins in the said sample would have tyrosine as a part of it which would give a postiive test with Millon;s reagent. Thus it can be used for urine sample.
E-1 In cysteine the SH group is closer to electronegative N and COOH group, thus can be oxidized readily, whereas, the methionine the sulfur is attached far from N and COOH and has an Me group on it which makes it differ in electron density and hence the reactions.
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