Protein concentration of Laemmli gel samples

To 10 µl boiled lysate (in Laemmli sample buffer) add 40µl water + 50µl 50% TCA. Ppt. 10 min. on ice. Spin and wash with 10% TCA. Resuspend pellet in 100 µl 1M NaOH, add 900 µl water and assay 100 µl by Bradford method.