This document summarizes an experiment to determine the amount of protein in milk samples using various methods including biuret, Lowry, Bradford, and BCA assays as well as SDS PAGE and Coomassie Blue staining. The experiment aimed to quantify the protein casein in different milk samples and compare the measured values to the amounts listed on product labels.

1. Got Protein?<br />The key pint in this experiment was the determination of the amount of protein present in a solution. There are various methods that can be used to determine the quantity of protein present; those are biuret, lowry, bradfor assay and BCA. The most known of the methods is the Coomassie Blue G dye. It is commonly used for staining proteins with the purpose of critical analysis. In this laboratory we analyzed the milk proteins with the objective of comparing the quantities obtain to the ones in the label of the product. This quantification of proteins was possible with the used of SDS Page. We were specifically looking for the protein caseine with 224 amino acids and with a weight of 24.97 kdalto. We work with various types of milk sample. After putting each sample in the SDS Page we were able of determining the absorbance. Through the absorbance we were able to calculate the mass of protein present and compare it to the labels of the product.<br />Cristina M. Cruz Irizarry<br />RISE Program<br />