title: Method for determining the average degree of substitution of o-vanillin derivatized porcine somatotropin.
abstract: Electrospray mass spectral observation directly on a sample of a derivatized protein, such as porcine somatotropin (pST), affords a method for evaluating the degree of substitution of this protein. Derivatization of the lysine residues and the terminal amino residue here by formation of a Schiff base with a small aromatic aldehyde (in this case, o-vanillin) affords stabilization of the protein so that it may be used in a controlled release veterinary pharmaceutical formulation. This method permits direct observation of substitutions, optimization of manufacturing procedures for producing a commercial product, and permits quality evaluation of material.
authors.affiliation: Analytical Research & Development Department, mailstop 8286-03, Pfizer Global Research & Development, Eastern Point Road, Groton, CT 06340, USA. thomas.r.sharp@pfizer.com
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Sharp
authors.forename: Ronald
authors.initials: R
authors.lastname: Morris
authors.forename: George J
authors.initials: GJ
authors.lastname: Horan
authors.forename: Linda H
authors.initials: LH
authors.lastname: Pezzullo
authors.forename: Justin G
authors.initials: JG
authors.lastname: Stroh
mesh_terms: D000447:Aldehydes / Q000032:analysis; D000595:Amino Acid Sequence; D000818:Animals; D001547:Benzaldehydes / Q000032:analysis*; D002623:Chemistry Techniques, Analytical / Q000379:methods; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D013006:Growth Hormone / Q000032:analysis* / Q000737:chemistry*; D008239:Lysine / Q000032:analysis / Q000737:chemistry; D013058:Mass Spectrometry; D008956:Models, Chemical; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013552:Swine
chemical_list: D000447:Aldehydes; D001547:Benzaldehydes; C060843:2-vanillin; D013006:Growth Hormone; D008239:Lysine