The Separation and Determination of Cyclic Imino Acids

Lactoperoxidase-catalyzed incorporation of thiocyanate ion into a protein substrate

“…Thin-Layer Chromatography. Chromatography of amino acid derivatives was performed on cellulose sheets (Eastman Kodak Co.) in four solvent systems (Block and Bolling, 1951;Piez et al, 1956): solvent A, ZerZ-amyl alcohol-2,6-lutidinewater, 19:19:12; solvent B, ZerZ-butyl alcohol-formic acidwater, 14:3:3; solvent C, sec-butyl alcohol-re/T-butyl alcohol-0.3% ammonium hydroxide, 4:1:3; and solvent D, ethanol-water-diethylamine, 77:23:2. Radioactive compounds were visualized by autoradiography and then removed from the cellulose sheets and radioactivity was determined as described above.…”

Purification and characterization of roseotoxin B, a toxic cyclodepsipeptide from Trichothecium roseum

“…A review of proline derivatives that might correlate with these data focused on methylproline. A quantitative method for cyclic imino acids (Piez et al, 1956) also pro-vided some qualitative information about the visible range spectrum of the stable colored complex that they form with ninhydrin in glacial acetic acid. When the component that forms a yellow product with ninhydrin was used, the spectrum contained one absorption maxima at 350 nm.…”

“…Tests for Cyclic Imino Acids. Aqueous solutions of the samples to be tested were combined with 0.15% ninhydrin in glacial acetic acid and placed in a boiling water bath for 35 min or left at room temperature for several hours following the procedure described by Piez et al (1956).…”

Amino acid sequence of roseotoxin B

“…The Rf of the spots were the same as those for standard L-isoleucine, Nmethyl-DL-valine, and frans-3-methylproline in the three solvent systems. The fact that the color development of peptide II with ninhydrin included a yellow color (transitional) and a final pink red that fluoresced red under long-wave ultraviolet light (Parmentier and Vanderhaeghe, 1960;Piez et al, 1956) was evidence for frcms-3-methylproline being the N-terminal amino acid of peptide II. This peptide also gave a positive test (blue color) with the isatin-zinc acetate reagent which is a test for proline and certain proline derivatives (Table II).…”