Recently we described a method for the determination of alanine based upon its conversion into acetaldehyde by the action of ninhydrin (1). A method for the measurement of glycine has been devised which involves its conversion by ninhydrin to formaldehyde; the latter is then measured by its reaction with chromotropic acid. Earlier methods for the measurement of glycine are less sensitive and sp...

The UV spectrum of pepstatin shows only end absorption. Strong absorptions centered at 1630cm"1 and 1540cm"1 in the infrared spectrum suggest that pepstatin is a kind of peptide. Pepstatin shows a negative reaction for ninhydrin, but positive for RydonSmith reagent. Pepstatin has no free basic function. It gives mono-methyl ester by treatment of diazomethane. The di-acetyl derivative of the met...

A new antibiotic, leucinostatin, was isolated from the culture filtrate of Fenicillium lilacinum. The antibiotic was obtained in the form of white prisms, decomposing at 131~136°C, and showing optical rotation [^]d2+644° (c 0.5, methanol). The ultraviolet absorption spectrum showed only an inflection at 220nm in methanol. The antibiotic gave a positive reaction to biuret and negative to ninhydr...

In such substrates RCOOH can represent not only substituted pteridines but a variety of organic acids, including many amino acids. However, hydrolytic activity seems to occur only when L-glutamate with a free a-carboxyl group is the donor of the amide nitrogen in the linkage. This specificity indicates that the enzyme may be thought of as a carboxypeptidase for glutamate. An enzyme with these p...

The photometric ninhydrin method described previously (1) for use in the chromatography of amino acids has been the subject of further study during the development of the Dowex 50-X4 procedure (2). The adjustment of the pH of the effluent fractions prior to analysis required by the earlier method has been largely eliminated by increasing the strength of the buffer in the reagent 5-fold. A secon...

In recent years, a number of photometric methods for the quantitative determination of ar-amino acids have been introduced (1, 2). These methods, based on reaction with ninhydrin in aqueous solution, are less satisfactory for the determination of imino acids.1 Grassmann and von Atnim (3) described reaction products of ninhydrin with imino acids and have suggested that these might be of use for ...