VON G. P()LYA in Z(~RICH. Einleitung. I. Die Entwicklungen dieser Arbeit setzen Untersuehungen yon Cayley fort. Cayley hat wiederholt kombinatorische Aufgaben behandelt, deren Zweck ist, die Anzahl gewisser >>B~ume>> zu bestimmen. 1 Einige seiner Aufgaben sind einer chemischea Interpretation f~hig: Die Anzahl der betreffenden >>B~ume>> ist gleich der Anzahl gewisser (theoretisch mSglicher) isomerer ehemischer Verbindungen. Die ausgedehnten numerischen Rechnungen Cayleys wurden yon mehreren Autoren, iusbesondere yon Chemikern nachgepriift und zum Teil berichtigt. Einen eigentlichen Fortschritt brachten meines Erachtens erst die Publikationen yon zwei amerikanischen Chemikern, yon ttenze und Blair, die nicht nur die numerischen Rechnungen Cayley's um ein gutes Stiick welter fiihrten, sondern aueh die Methode verbesserten und weitere Klassen yon Verbindungen in die Berechnung einbezogen. ~ Ohne unmittelbaren Zusammenhang mit den Cayleyschen Fragen wurde andererseits erkannt, durch'Lunn and Senior 3, dass gewisse Isomerenzahlen in enger Beziehung zu den Permutationsgruppen stehen.In der vorliegenden Arbeit werde ich die Cayleysche Fragestellung in ver-

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The lupane triterpenoid lupeol, the ursane triterpenoid alpha-amyrin and esters of these compounds are present in the bark of roots of Alstonia boonei (Apocynaceae) and have anti-inflammatory properties. alpha-Amyrin is a competitive inhibitor of bovine trypsin and chymotrypsin (Ki values 29 microM and 18 microM, respectively). Lupeol linoleate, lupeol palmitate and alpha-amyrin linoleate are non-competitive inhibitors of trypsin (Ki values 7 microM, 10 microM and 16 microM, respectively). alpha-Amyrin linoleate is also a non-competitive inhibitor of chymotrypsin (Ki value 28 microM). Lupeol is a competitive inhibitor of both trypsin and chymotrypsin (Ki values 22 and 8 microM, respectively). alpha-Amyrin palmitate is a potent non-competitive inhibitor of chymotrypsin (Ki 6 microM). Lupeol, alpha-amyrin and the palmitic and linoleic acid esters of these compounds are ineffective or very weak as inhibitors of porcine pancreatic elastase and of Lucilia cuprina and Helicoverpa punctigera leucine aminopeptidases. These hydrophobic triterpenoids represent further examples of anti-inflammatory triterpenoids that are PKA inhibitors as well as being selective protease inhibitors.

A soluble protein that interacts with a range of cytokinins was extensively purified from wheat (Triticum aestivum L.) germ. This protein has a K d for kinetin of 2×10(-7) M. The binding of kinetin to the protein is inhibited by low concentrations of synthetic and naturally-occurring cytokinins including N(6)-benzyladenine, N(6)-benzyladenosine, kinetin riboside, N(6)-dimethylallyladenine, N(6)-dimethylallyladenosine, zeatin, zeatin riboside, N(6)-dimethyladenine and N(6)-dimethyladenosine. Adenine, adenosine and several non-N(6)-substituted adenine derivatives were ineffective as inhibitors of kinetin binding. While N(6)-butyryl-3',5'-cyclic AMP, N(6),2-O'-dibutyryl-3',5'-cyclic AMP and 2',3'-cyclic AMP inhibited binding of kinetin to the protein, 3',5'-cyclic AMP was ineffective. The kinetin-binding protein is heat-labile and pronase-sensitive. Kinetin-binding activity exactly co-chromatographs with a single peak of carbohydrate and protein on gel-filtration and is displaced from concanavalin A-Sepharose 4B by α-methylglucoside. On gel filtration, the kinetin-binding protein behaves as a soluble protein with an apparent molecular weight of 180,000 daltons.

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