the presence of urea and split the molecule into four peptides (disulfide bonds were reduced).Reassociation was prevented with an alkylating agent such as iodoacetate. Hinge region】 urea&iodoategtg Separation by gel filtretion L chain Hchain Hchain 50 kD 25 kD U8→ Elution volume With the availability of homogeneous Igs,it soon became evident that the two H chains were always identical in a given molecule,as were the L chains.H chains contain about 440 amino acids,whereasLchains possessed about 220 amino acids.The variable (V)region different between two L chains from different molecules.The constant region of the L chain is the same amino acid sequence in different amino acids.A similar pattern was found in the H chain.The variable region in the H chain is only about 25%as long as the C region.Each domain consist of about 110 amino acids.Each domain Contains a intrachain disulfide bridge of about 60 residues. Heavy Chains are distinguishable on the basis of amino acid sequences in their Cregion and by the number of domains.L chains are distinguished by the amino acid sequences in their C regions.Antibodies contain kappa or lambda chains but not one of each. Only about 5%of mouse antibodies have lambda chains where as 40%of humans contain kappa chains.the presence of urea and split the molecule into four peptides (disulfide bonds were reduced). Reassociation was prevented with an alkylating agent such as iodoacetate. The chains were separated by size on Sephadex column. They found two L chains with a molecular weight of 25 kD and two heavy chains with 50 kD. With the availability of homogeneous Igs, it soon became evident that the two H chains were always identical in a given molecule, as were the L chains. H chains contain about 440 amino acids, whereas L chains possessed about 220 amino acids. The variable (V) region different between two L chains from different molecules. The constant region of the L chain is the same amino acid sequence in different amino acids. A similar pattern was found in the H chain. The variable region in the H chain is only about 25% as long as the C region. Each domain consist of about 110 amino acids. Each domain Contains a intrachain disulfide bridge of about 60 residues. Heavy Chains are distinguishable on the basis of amino acid sequences in their C region and by the number of domains. L chains are distinguished by the amino acid sequences in their C regions. Antibodies contain kappa or lambda chains but not one of each. Only about 5% of mouse antibodies have lambda chains where as 40% of humans contain kappa chains