Labeling proteins with dyes that are insoluble or only sparingly soluble in water

Abstract

The proteins in a biological sample that is sought to be analyzed for its protein composition by an electrophoretic or chromatographic procedure are coupled to a dye in an unusually efficient manner by combining the sample with a solid dry composition containing the dye a buffering agent, and in preferred embodiments, a denaturing agent as well. The solid and dry form of the composition prevents the dye from deteriorating or decomposing, and the combination of components in the composition allows the dye to couple to the proteins in a relatively uniform manner with no overstaining of the protein when the composition and the sample are heated together and held at an elevated temperature for a short period of time.

1 - 10 . (canceled)  
   
   
       11 . A receptacle for a biological sample, said receptacle having an inner surface coated with a solid dry composition comprising a fluorescent dye whose solubility in water is less than 5 μg/mL at 25° C. and which is capable of coupling to a protein.  
   
   
       12 . A receptacle in accordance with  claim 11  in which said fluorescent dye is a member selected from the group consisting of 4,4-difluoro-5,7-diphenyl-4-bora-3a,4a-diaza-s-indacene-3-propionic acid, succinimidyl ester, 4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-propionic acid, succinimidyl ester, and 6-(((4,4-difluoro-5-(2-pyrrolyl)-4-bora-3a,4a-diaza-s-indacene-3-yl)styryloxy)acetyl)aminohexanoic acid, succinimidyl ester.  
   
   
       13 . A receptacle in accordance with  claim 11  in which said fluorescent dye is 4,4-difluoro-5,7-diphenyl-4-bora-3a,4a-diaza-s-indacene-3-propionic acid, succinimidyl ester.  
   
   
       14 . A receptacle in accordance with  claim 11  in which said solid dry composition further comprises a polymeric binder.  
   
   
       15 . A receptacle in accordance with  claim 14  in which said polymeric binder is a member selected from the group consisting of polyvinyl alcohol, polyethylene glycol, and polyinylpyrrolidone.  
   
   
       16 . A receptacle in accordance with  claim 14  in which said solid dry composition has a polymeric binder:dye weight ratio of from about 1:1 to about 10:1.