※ 引述《[email protected] (因为有你所以精彩)》之铭言： : 虽然以前曾经懂过，现在又全都忘光了， : 就是在做SDS-PAGE时，Stacking gel的目的是让sample全在一个起跑点， : 好像跟当时的pH以及glycine有关， : 但是细节有点忘了， The outline of the answer is given here. The pH of stacking gel is about 6.7 (or 6.8?) whereas the pH of the running gel (or separation gel) is about 8.9 (or 8.8). At pH 6.7, the net charge of Gly is close to zero, so the mobility of Gly is very low. Because of this, the 20-25 ul of protein sample can be compressed into a very thin layer in the stacking gel. Also, the percentage of acrylamide in the stacking gel is very low (compared with in separation gel ), so very little molecular sieving occurs here. Thus, proteins of different molecular weights are not separated in the stacking gel, and are condensed to a thin layer. -- "...What science has accomplished is to tell us that this happens because organisms contain genes in them and that the future organism is written in this 'somehow'. And 'somehow' is what we have to explain. We have to say not 'somehow', but 'how'. " Syndney Brenner -- ※ Origin: 台大电机 Maxwell 站 ◆ From: pool-151-197-112-37.phil.east.verizon.n