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A report in an Ecuadorian anthropological monograph that Petunia violacea was used as a hallucinogen by some native South American people under the name Shanin. (Alvear, 1971) stimulated interest in the ethnobotanical literature (Schultes, 1975). This was particularly interesting because the species is a member of the alkaloid-rich Solanaceae family. No reports of its containing alkaloids have been published to date (Raffauf, 1970). We have unsuccessfully attempted to isolate an alkaloid from this plant grown in the greenhouse, and recently interviewed the author of the original report. This communication will summarize the results of the laboratory work and the interview.

After comparing several methods of protein determination it was concluded that when polyphenolic compounds are present the most reliable method for protein is the Bradford procedure using Coomassie Brilliant Blue G-250.

The Δ 5 - β -3-OH sterols, cholesterol, ergosterol, sitosterol, and stigmasterol, reversed the antifungal activity of pimaricin on S. cerevisae while mevalonic acid, squalene and lanosterol were inactive in this respect. Several explanations for this effect were discussed.

The 2-, 4-, and 6-pyridones related to 1-methylnicotinonitrile have been synthesized and their properties compared. The 4-pyridone is a new compound and the 2-pyridone has not been obtained synthetically before. The 4- and 6-pyridones are identical to two of the products obtained from enzymatic oxidation of nicotinonitrile methiodide.

The crude extract of pyridinium oxidizing enzymes from Ricinus communis seedlings was resolved into three enzyme entities by DEAE column chromatography. Their optimal pH, temperature stability, activation energies and substrate specificities are similar. Analysis of their enzymatic products have shown that each of these enzymes catalyses the oxidation of 1-methyl-nicotinonitrile perchlorate to form 4- and 6-pyridones.

Pyridinium oxidase B from Ricinus communis, initially separated by DEAE cellulose column chromatography, was further purified. The fraction with the highest activity from Ecteola cellulose column still showed a trace of impurities in polyacrylamide gel electrophoresis. Molecular weight estimation by sucrose gradient ultracentrifugation showed that pyridinium oxidase B has an apparent molecular weight of approximately 250,000. The rate of 4- and 6-pyridone formation in the catalytic process was studied. The ratio of the 6-pyridone to 4-pyridone ranged from 3·5 to 4·1. The Km for 1-methyl-nicotinonitrile perchlorate was found to be 5 × 10−4 M for pyridinium oxidase B, and it decreased with increasing pH. An approximate pKa of 9:9 was obtained for the ionizing group involved in the enzymatic reaction. The Km values for its substrate analogues, except 1-methyl-3-acetyl pyridinium, were found to be the same. However, the value of Vm increased as the dipole moment of the 3 substituent increased. The present evidence indicates that the positively charged quaternary nitrogen is necessary for the enzyme-substrate binding, and a strong electron withdrawing group will enhance the oxidation reaction. The enzyme resembles aldehyde and xanthine oxidase in its ability to oxidize a wide variety of nitrogenous compounds.

A crude enzyme system prepared from young castorbean seedlings catalyzes the oxidation of 1-methylnicotinonitrile to the corresponding 4- and 6-pyridones. The implications of this reaction for the biosynthesis of the alkaloid ricinine are considered. Other pyridone alkaloids might be formed by similar reactions.

When dilute aqueous solutions of liver alcohol dehydrogenase were exposed to X-irradiation, there was much more inactivation in the presence of bicarbonate buffer than in phosphate buffer or in distilled water. The effect was not due to the action of any stable intermediates produced by irradiation of bicarbonate buffer, nor does it seem likely that enzyme is converted by irradiation to some long-lived metastable state whose destruction is precipitated by the presence of bicarbonate. Enzyme and bicarbonate must be present simultaneously for the effect to be observed. Several other enzymes have been investigated in this regard, and possible mechanisms discussed.

At least seven species ( Chrozophora plicata, Jatropha gossypifolia, Ricinus communis, Tragia involucrata, Trewia nudiflora, Acalypha hispida, Synadenium grantii ) in the family Euphorbiaceae have shown enzymatic oxidizing activity on salts of 1-methyl-nicotinotrile. 4- and 6-pyridones were shown to be the enzymic products in vitro for both Trewia nudiflora and Ricinus communis .

Extracts of Papaver somniferum that had peroxidase activity were ineffective in catalysing oxidation of reticuline. Two peroxidases were purified from young seedlings and their properties examined. Only one of them was active toward indole-3-acetic acid (IAA).

Isotopic tracer experiments confirmed that glycerol and succinic acid are good precursors of the pyridine ring of ricinine in castor bean plants. Tritium from C-2 was lost from tritiated glycerol while tritium from C-1 was retained. Thus a derivative of dihydroxyacetone is likely to be intermediate. By simultaneous feeding of glycerol-1-(3)-[3H] and succinic acid-2(3)-[14C], it was hoped to find precursors of ricinine containing both labels, but none could be found. There was no evidence for the appearance of labeled quinolinic acid, which is presumed to be a precursor of ricinine.

In contrast to a previous report no free arginine, agmatine, or other low-molecular-weight guanido compound could be detected in seeds of Ricinus communis (Euphorbiaceae). A heat-stable, arginine-containing protein was isolated and identified with a previously known allergen.