Homogenous populations of molecules

Abstract

The invention provides populations of molecules that are prepared as, or treated to become, homogeneous for one or more molecular characteristics. In an aspect, the invention relates to molecular weight standards that may be used to determine the molecular weight or apparent molecular weight of uncharacterized molecules, such as proteins and nucleic acids, as well as in other applications. In one aspect, the molecular weight standards are pre-stained.

What is claimed is: 
     
         1 . A purified homogeneous population of a species of macromolecule that has been made at least partly homogeneous for one or more molecular characteristics. 
     
     
         2 . The homogeneous population of a species of macromolecule of  claim 1 , wherein the molecular characteristic is the presence or absence of the species of the macromolecule. 
     
     
         3 . The homogeneous population of a species of macromolecule of  claim 1 , wherein the molecular characteristic is one that can be used to distinguish one molecular species from another. 
     
     
         4 . The homogeneous population of a species of macromolecule of  claim 1 , wherein the molecular characteristic is one that can be detected or measured in other molecular species. 
     
     
         5 . The homogeneous population of a species of macromolecule of  claim 1 , wherein the molecular characteristic is molecular weight. 
     
     
         6 . The homogeneous population of a species of macromolecule of  claim 1 , wherein said population has been made at least partly homogeneous by the addition, removal or alteration of a chemical modification. 
     
     
         7 . The homogeneous population of a species of macromolecule of  claim 1 , wherein said macromolecule is a nucleic acid. 
     
     
         8 . The homogeneous population of a species of macromolecule of  claim 1 , wherein said macromolecule is a protein. 
     
     
         9 . The homogeneous population of a species of macromolecule of  claim 6 , wherein said macromolecule is a protein. 
     
     
         10 . The homogeneous population of a species of protein of  claim 6 , wherein said chemical modification is a post-translational modification. 
     
     
         11 . A molecular standard comprising a purified homogeneous population of a species of macromolecules that has been made at least partly homogeneous for one or more molecular characteristics. 
     
     
         12 . The molecular standard of  claim 11 , further comprising a second population of a species of macromolecule. 
     
     
         13 . The molecular standard of  claim 11 , wherein said molecular characteristic is molecular weight. 
     
     
         14 . The molecular standard of  claim 11 , wherein said purified homogeneous population of a species of macromolecules comprises a plurality of species with molecular weights greater than 300 kDa. 
     
     
         15 . The molecular standard of  claim 12 , wherein at least one of said species of macromolecules is pre-stained. 
     
     
         16 . A method of preparing a set of molecular standards comprising combining or co-producing populations of two or more molecules having at least one known value for at least one molecular characteristic, wherein at least one of said populations of two or more molecules is a homogeneous population of a species of macromolecule that has been made at least partly homogeneous for one or more molecular characteristics. 
     
     
         17 . A method of estimating or determining a molecular characteristic of an uncharacterized molecule, comprising:
 (a) detecting a signal from said uncharacterized molecule, said signal being indicative of said molecular characteristic;   (b) detecting a signal from a homogeneous population of a species of macromolecule that is at least partly homogeneous for said molecular characteristics, said signal being indicative of said molecular characteristic; and   (c) comparing the signal of (a) with the signal of (b).   
     
     
         18 . The method of  claim 17 , wherein the uncharacterized molecule is a protein or a nucleic acid. 
     
     
         19 . A method for preparing a protein standard, comprising modifying an isolated protein by removing, adding, or modifying a chemical modification of the isolated protein to produce a modified protein, thereby preparing the protein standard. 
     
     
         20 . The method of  claim 19 , wherein the chemical modification of the isolated protein is a post-translational modification. 
     
     
         21 . The method of  claim 19 , wherein the modification of the isolated protein is carried out for a population of isolated proteins to produce an at least partially homogeneous population of the protein standard. 
     
     
         22 . The method of  claim 21 , wherein the method is carried out for a series of isolated proteins having different molecular characteristics. 
     
     
         23 . The method of  claim 22 , wherein the method is carried out for a population of each of a series of isolated proteins having different molecular characteristics resulting in a series of at least partially homogeneous populations of proteins. 
     
     
         24 . The method of  claim 21 , wherein the at least partially homogeneous population of proteins are completely homogeneous. 
     
     
         25 . The method of  claim 21 , wherein the at least partially homogeneous population of proteins is a population of high molecular weight proteins. 
     
     
         26 . The method of  claim 25 , wherein the population of proteins comprises a laminin polypeptide. 
     
     
         27 . The method of  claim 21 , wherein the at least partially homogeneous population of proteins is a population of a high molecular weight standards. 
     
     
         28 . The method of  claim 23 , wherein the series of at least partially homogeneous populations of proteins comprises a series of high molecular weight proteins. 
     
     
         29 . The method of  claim 21 , further comprising using the modified protein as a standard in an analytical method. 
     
     
         30 . The method of  claim 19 , wherein the removing, adding, or modifying comprises adding, removing, or modifying from the isolated protein, a phosphate group, a carbohydrate group, an amide, an N-terminal modification, an isoprenoid group, a selenium group, a sulfate group, a fatty acid group, a hydroxyl group, or an ubiquitin group. 
     
     
         31 . The method of  claim 21 , wherein the modification comprises removing a phosphate group from the population of isolated proteins. 
     
     
         32 . The method of  claim 21 , wherein the modification is carried out for a population of a laminin polypeptide. 
     
     
         33 . The method of  claim 32 , wherein the modification is one or more of deglycosylation, reduction, or alkylation. 
     
     
         34 . The method of  claim 32 , wherein the modification is reduction. 
     
     
         35 . An isolated molecular weight standard produced according to the method of  claim 19 . 
     
     
         36 . An isolated high molecular weight standard produced according to the method of  claim 25 . 
     
     
         37 . An isolated high molecular weight protein standard, wherein the protein standard has an apparent molecular weight of at least 400 kDa by SDS PAGE. 
     
     
         38 . The isolated high molecular weight protein standard of  claim 37 , wherein the protein standard is a laminin. 
     
     
         39 . The isolated high molecular weight protein standard of  claim 37 , wherein the protein standard does not comprise at least one post-translational modification that is usually present on the protein in vivo. 
     
     
         40 . The isolated high molecular weight protein standard of  claim 37 , wherein the protein standard has been chemically modified with respect to a post-translational modification. 
     
     
         41 . The isolated high molecular weight protein standard of  claim 37 , wherein the protein standard does not comprise a phosphate group, a carbohydrate group, an amide, an N-terminal modification, an isoprenoid group, a selenium group, a sulfate group, a disulfide bond, a fatty acid group, a hydroxyl group, or a ubiquitin group. 
     
     
         42 . The isolated high molecular weight protein standard of  claim 38 , wherein the protein standard does not comprise a carbohydrate group or a disulfide bond. 
     
     
         43 . The isolated high molecular weight protein standard of  claim 42 , wherein the protein standard comprises an alkyl group. 
     
     
         44 . The isolated high molecular weight protein standard of  claim 37 , wherein the protein standard is at least partially homogeneous. 
     
     
         45 . The isolated high molecular weight protein standard of  claim 37 , wherein the protein standard is completely homogeneous. 
     
     
         46 . The isolated high molecular weight proteins standard of  claim 37 , wherein the protein standard is a pre-stained standard. 
     
     
         47 . A kit comprising an isolated high molecular weight standard of  claim 37 . 
     
     
         48 . The kit of  claim 47 , wherein the kit further comprises a molecular weight protein standard other than a high molecular weight protein standard. 
     
     
         49 . The kit of  claim 48 , wherein the protein standards are pre-stained standards. 
     
     
         50 . The kit of  claim 48 , wherein the kit comprises a set of protein standards, wherein at least 2 of the protein standards are high molecular weight protein standards.