Determination of the N-terminal Amino-acid in Polypeptides and Proteins

Photodynamic action of porphyrins on amino acids and proteins. I. Selective photooxidation of methionine in aqueous solution

“…Amino End-Group Analysis. The amino-terminal groups of the CNBr cleavage products were determined by reaction of lysozyme with 2-chloro-3,5-dinitropyridine, following the method of Signor et al (1964). The 2,4-dinitropyridyl protein was hydrolyzed in 6 n HC1 within evacuated sealed vials for 30 min at 100°; under these conditions, the quantitative detachment of the 2,4-dinitropyridylamino acids is achieved.…”

Reductive conversion of N-terminal pyroglutamyl into prolyl residues in polypeptides and proteins

“…The use of 2-chloro-3,5-dinitropyridine as a reagent for identification and assay of N-terminal amino acids (Signor et al, 1964) was explored as an alternative to the more common methods. Despite the sensitivity of 3.5-dinitropyridylamino acid to light (slightly greater than that of DNP-amino acids), the ease of manipulation, hydrolytic cleavage, and separation of products by thin-layer chromatography invite further consideration of the method.…”

“…Stability of 3,5-Dinitropyridylproline to Acid Hydrolysis. A sample of 3,5-dinitropyridylprolylglycine, which had been prepared according to the general procedure of Signor et al (1964), was dissolved in a mixture of 2 ml of 60% formic acid and 2 ml of concentrated hydrochloric acid and the solution maintained at 60°for 13 hr. Following removal of solvent and ethyl acetate extraction of the residue, 3,5-dinitropyridylproline was purified by thin-layer chromatography and assayed " Crystalline material was lyophilized prior to reduction.…”

The subunits of chemically treated proteoglycan isolated from bovine nasal cartilage

“…Amino end-group analysis was carried out by the 2-chloro-3,5-dinitropyridine method (Signor, Biondi, Terbojevich & Pajetta, 1964), as described by Serafini-Fracassini (1968). The dinitropyridyl-substituted material was hydrolysed with constant-boiling HCI in sealed tubes, under N2, at 60°C for lOh.…”