Theodore T. Otani

A synthesis and resolution of DL-serine.

Abstract A single-step synthesis of dl -serine from the interaction of formaldehyde and glycine in an alkaline aqueous solution containing catalytic amounts of copper sulfate is described. The reaction proceeds in addition with the formation of a second as yet unidentified ninhydrin-reactive substance with an empirical formula of C 4 H 9 NO 4 . Separation of the two products from each other and from any unreacted glycine is readily achieved with the aid of a Dowex 50 column. The elemental analyses, chromatographic behavior, and infrared absorption spectrum of the serine ultimately secured were identical with those shown by an authentic sample of dl -serine. Additionally, a resolution of dl -serine as its acetyl derivative via the l -directed asymmetric hydrolytic action of hog renal acylase I and a racemization of optically active serine by treatment with acetic anhydride in aqueous pyridine are presented.

Studies on hydroxyamino acids. I. Synthesis of some α-alkylated serines

Abstract The coproduct which accompanies serine formation upon treatment of an aqueous alkaline solution of glycine with formaldehyde, in the presence of catalytic amounts of cupric ion, has been identified as α-(hydroxymethyl)serine. The latter product, which could be induced to form almost exclusively in the same reaction system solely by increasing the cupric ion concentration, was characterized by (a) decarboxylation with ninhydrin, (b) deamination with nitrous acid, (c) oxidative degradation with periodate and (d) reduction with hydriodic acid. An alternate synthesis of this material was achieved in high yield via the cupric ion-mediated condensation of serine and formaldehyde in alkaline aqueous solution. Substitution of the serine component in the last-mentioned reaction with alanine permitted the facile single-step synthesis of α-methylserine; comparable substitution with α-amino-n-butyric acid led to α-ethylserine.

Studies on hydroxyamino acids. II. A general synthesis of α-amino-β-hydroxy acids

Abstract The single-step synthesis of β-hydroxyleucine, β-hydroxynorleucine, β-hydroxyaspartic acid and β- p -nitrophenylserine via the cupric ion-catalyzed condensation of glycine with isobutyraldehyde, n -butyraldehyde, glyoxylic acid, and p -nitrobenzaldehyde, respectively, in an aqueous alkaline medium, is described. Description is given of the use of a similar procedure with aliphatic and aromatic aldehyde reactants other than those mentioned, as well as the general application of this procedure to the synthesis of α-amino-β-hydroxy acids.

Isozymes of glutamic-oxalacetic transaminase in some rat hepatomas

Abstract Water extracts of GOT from livers of normal and host rats, and from rat hepatomas 7316-B, 5123-A, 5123-B, 7288-C, and 3683 were made. The specific activities of these hepatomas varied over a wide range. Upon electrophoresis on granular starch block, the extracts of all five hepatomas, like that of the normal liver, and that of the host liver, exhibited two isozymes. The mobilities of these isozymes were identical with the respective isozymes in the different hepatomas, as well as with the isozymes in the normal and host livers. The relative quantitative distribution of each isozyme varied with the different hepatomas, and with the normal and host livers. However, it appeared that, at least with the five hepatomas studied here, the “anionic” to the “cationic” GOT ratio was higher in the hepatomas than in the normal.

Studies on hydroxyamino acids. III. Effect on growth of Escherichia coli 9637

α-(Hydroxymethyl)serine, α-methylserine, α-ethylserine, β-hydroxyleucine, β-hydroxynorleucine, β-hydroxyaspartic acid, and β-(p-nitro)phenylserine were tested for biological activity in an Escherichia coli system. Of these, β-hydroxyaspartic acid and β-hydroxyleucine exhibited marked growth inhibitory activity. Certain naturally occurring amino acids, most of which were structurally similar to the inhibiting β-hydroxyamino acids, were shown to be capable of completely nullifying these inhibitory effects, while others, which were probably metabolically related to these amino acids, were capable of doing so to a lesser and varying extent. It appears that the inhibition is of the competitive type.