Profile: 21st Century Biochemicals, LLC supplies custom antibodies and custom peptides. We provide mg to grams of linear peptides, libraries, cyclized peptides (both disulfide & covalent bonded), as well as peptides with a variety of modifications like phosphorylation, biotinylation, acylation, unusual & D-amino acids, dyes. We offer a wide range of mass spectroscopy & related analytical services for applications such as mass determination, post-translational analysis (like phosphorylation & glycosylation), peptide mapping, enzymatic digestions & protein/peptide sequence determination, and complex mixture analysis.