Sensitive silver staining of protein in sodium dodecyl sulfate-polyacrylamide gels using an azo dye, calconcarboxylic acid, as a silver-ion sensitizer.
A highly sensitive silver staining method for detecting proteins in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was developed. It is based on the silver nitrate staining method but also employs an azo dye, calconcarboxylic acid (NN), as a silver-ion sensitizer. It increases silver binding on protein bands or spots by the formation of a silver-dye complex and also increases the reducing power of silver ions to metallic silver by NN itself with formaldehyde. After a 2 h gel fixing step, the protocol including sensitization, silver-ion impregnation, and reduction steps can be completed in 1 h. The sensitivity is superior to that of silver stain with glutardialdehyde as a silver-ion sensitizer. The detection limit of NN-silver stain is 0.05-0.2 ng protein. Considering the high sensitivity without using glutardialdehyde, the NN-silver stain would be useful for routine silver staining of proteins.
College of Pharmacy, Chonnam National University, Kwangju, South Korea.
Li-Tai
LT
Jin
Sun-Young
SY
Hwang
Gyurng-Soo
GS
Yoo
Jung-Kap
JK
Choi
D001391:Azo Compounds / Q000737:chemistry*; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000737:chemistry; D005557:Formaldehyde / Q000737:chemistry; D005976:Glutaral / Q000737:chemistry; D009284:Naphthols / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry*; D016622:Silver Staining; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*
D001391:Azo Compounds; D009284:Naphthols; D011506:Proteins; D005557:Formaldehyde; D012967:Sodium Dodecyl Sulfate; C084567:calconcarboxylic acid; D005976:Glutaral