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.

1 - 50 . (canceled) 
     
     
         51 . A molecular weight standard comprising a purified population of proteins that have been treated by the addition, removal or modification of chemical groups so as to be made at least partly homogenous for molecular weight as a molecular weight standard, each population having a differing molecular weight. 
     
     
         52 . The molecular weight standard according to  claim 51 , wherein the molecular weight standard comprises a plurality of purified population of proteins. 
     
     
         53 . The molecular weight standard according to  claim 51 , wherein the population has been treated by post translational modification. 
     
     
         54 . The molecular weight standard according to  claim 51 , wherein the population of proteins is a population of a laminin polypeptide. 
     
     
         55 . A molecular weight standard comprising a purified homogeneous population of a protein that has been made at least partly homogeneous for molecular weight, wherein the population has been modified by removing, adding or modifying a chemical modification of the protein. 
     
     
         56 . The molecular weight standard of  claim 55 , further comprising a second population of a species of protein, wherein optionally said second population has been made at least partly homogenous for molecular weight. 
     
     
         57 . The molecular weight standard of  claim 56 , wherein at least one of said species of macromolecules is pre-stained. 
     
     
         58 . The molecular weight standard of  claim 55 , wherein said purified homogeneous population of a species of protein comprises a plurality of species with molecular weights greater than 300 kDa. 
     
     
         59 . The molecular weight standard of  claim 55 , wherein the homogenous population is a laminin polypeptide. 
     
     
         60 . The molecular weight standard of  claim 59 , wherein the laminin polypeptide lacks phosphate groups. 
     
     
         61 . The molecular weight standard of  claim 59 , wherein the laminin polypeptide lacks a carbohydrate group or a disulphide bond, and optionally comprises an alkyl group. 
     
     
         62 . The molecular weight standard of  claim 59 , wherein the laminin polypeptide is a laminin protein subunit, wherein the laminin polypeptide is selected from a laminin alpha, beta and gamma subunit. 
     
     
         63 . The molecular weight standard of  claim 55 , wherein the series of isolated proteins comprises three laminin polypeptides. 
     
     
         64 . The molecular weight standard of  claim 63 , wherein the laminin polypeptide(s) are a laminin alpha subunit, a laminin beta subunit and a laminin gamma subunit. 
     
     
         65 . A method for preparing a protein standard for use in a molecular weight 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, 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, and further wherein the method is carried out on a series of isolated proteins having different molecular weights. 
     
     
         66 . The method of  claim 65 , wherein the chemical modification of the isolated protein is a post-translational modification. 
     
     
         67 . The method of  claim 65 , 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. 
     
     
         68 . The method of  claim 67 , wherein the series of at least partially homogeneous populations of proteins comprises a series of high molecular weight proteins. 
     
     
         69 . The method of  claim 65 , wherein the at least partially homogeneous population of proteins are completely homogeneous. 
     
     
         70 . The method of  claim 65 , wherein the at least partially homogeneous population of proteins is a population of high molecular weight proteins. 
     
     
         71 . The method of  claim 65 , wherein the population of proteins comprises a laminin polypeptide. 
     
     
         72 . The method of  claim 65 , 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. 
     
     
         73 . The method of  claim 65 , wherein the modification comprises removing a phosphate group from the population of isolated proteins. 
     
     
         74 . The method of  claim 65 , wherein the modification is one or more of deglycosylation, reduction, or alkylation. 
     
     
         75 . The method of  claim 65 , wherein the modification is reduction. 
     
     
         76 . An isolated molecular weight standard obtainable according to the method of  claim 65 . 
     
     
         77 . An isolated high molecular weight protein standard, wherein the protein standard has an apparent molecular weight of at least 400 kDa by SDS PAGE wherein the protein standard does not comprise at least one posttranslational modification that is usually present on the protein in vivo. 
     
     
         78 . The isolated high molecular weight protein standard of  claim 77 , wherein the protein standard is a laminin. 
     
     
         79 . The isolated high molecular weight protein standard of  claim 77 , wherein the protein standard has been chemically modified with respect to a post-translational modification. 
     
     
         80 . The isolated high molecular weight protein standard of  claim 77 , wherein the protein standard lacks at least one post-translational modification selected from the list of 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, and a ubiquitin group. 
     
     
         81 . The isolated high molecular weight protein standard of  claim 77 , wherein the protein standard does not comprise a carbohydrate group or a disulfide bond. 
     
     
         82 . The isolated high molecular weight protein standard of  claim 77 , wherein the protein standard comprises an alkyl group. 
     
     
         83 . The isolated high molecular weight protein standard of  claim 77 , wherein the protein standard is a pre-stained standard. 
     
     
         84 . A kit comprising an isolated high molecular weight standard of  claim 77 . 
     
     
         85 . A kit comprising the molecular weight standard of  claim 55 . 
     
     
         86 . The kit of  claim 85 , wherein the kit further comprises a molecular weight protein standard other than a high molecular weight protein standard. 
     
     
         87 . The kit of  claim 85 , wherein the protein standards are prestained standards. 
     
     
         88 . The kit of  claim 85 , wherein the kit comprises a set of protein standards, wherein at least 2 of the protein standards are high molecular weight protein standard. 
     
     
         89 . A purified homogeneous population of a species of macromolecule that has been made at least partly homogeneous for molecular weight. 
     
     
         90 . The homogeneous population of a species of macromolecule of  claim 89 , wherein said population has been made at least partly homogeneous by the addition, removal or alteration of a chemical modification. 
     
     
         91 . The homogeneous population of a species of protein of  claim 89 , wherein said chemical modification is a post-translational modification. 
     
     
         92 . 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.