Macromolecule analysis employing nucleic acid encoding

A composition comprising:

• (a) one or more solid supports, wherein each solid support comprises at least 100,000 peptide molecules covalently attached to the solid support, wherein
• (i) each of the at least 100,000 peptide molecules is associated with a nucleic acid tag;
• (ii) the at least 100,000 peptide molecules comprise molecules of at least 100 different peptides;
• and
• (iii) adjacent peptide molecules on the solid support are spaced apart from each other on a surface or within a volume of the solid support at an average distance of about 50 nm or greater;
• and
• (b) a plurality of binding agents each bound to one of the peptide molecules, wherein the plurality of binding agents comprises at least 3 different binding agents, wherein each of the at least 3 different binding agents is (i) bound to a N-terminal amino acid (NTAA) residue or C-terminal amino acid (CTAA) residue of a peptide molecule of the peptide molecules, and (ii) selective for a different peptide component, wherein the different peptide component is a different N-terminal amino acid (NTAA) residue or a different C-terminal amino acid (CTAA) residue of the peptide molecules.