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Solanaceous medicinal plants produce tropane alkaloids (TAs). We discovered a novel gene from Atropa belladonna, AbPPAR, which encodes a phenylpyruvic acid reductase required for TA biosynthesis. AbPPAR was specifically expressed in root pericycles and endodermis. AbPPAR was shown to catalyze reduction of phenylpyruvic acid to phenyllactic acid, a precursor of TAs. Suppression of AbPPAR disrupted TA biosynthesis through reduction of phenyllactic acid levels. In summary, we identified a novel enzyme involved in TA biosynthesis.

Binding behaviors of two cucurbit[n]urils (CB[n]) hosts with the [CH3bpy(CH2)6bpyCH3]4+ (bpy = 4,4'-bipyridinium) guest were investigated by 1H NMR and MALDI-TOF-MS experiments. While the CB[6] and CB[7] form [2]pseudorotaxanes with the host located over the hexamethylene chain of the guest, only the CB[7] forms a [3]pseudorotaxane with both host molecules residing over the bipyridinium groups. The initial CB[7] host vacates the inclusion of the hexamethylene chain as a result of the electrostatic and steric repulsions that would arise in simultaneous binding of adjacent aliphatic and aromatic portions of the guest.

The (E)-1-ferrocenyl-2-(1-methyl-4-pyridinium)ethylene cation, (E)-FcMPE+, forms a very stable guest−host complex (KCB7 = (1.3 ± 0.5) × 1012 M-1) in aqueous solution with cucurbit[7]uril (CB[7]). The 1H NMR, ES-MS, and UV−visible spectra are consistent with 1:1 {(E)-FcMPE·CB[7]}+ species formation, in which the CB[7] encapsulates the ferrocenylethylene portion of the guest. The reduction potential of the (E)-FcMPE2+/+ couple increases slightly (+0.03 V) in the presence of CB[7], while the rate constant for the oxidation of (E)-FcMPE+ by Co(dipic)2- (dipic2- = 2,6-pyridinedicarboxylate) decreases significantly. UV−visible spectra of (E)-FcMPE+ in the absence and in the presence of CB[7] during photoirradiation demonstrate that the photoisomerization to (Z)-FcMPE+ is fully inhibited and photostabilization of (E)-FcMPE+ is dramatically enhanced upon inclusion in CB[7].

The microporosity of ordered mesoporous aluminosilicates assemblied from zeolite nanoclusters is investigated by catalytic reactions with various probing molecules. At first, the samples are treated by bulky basic organic molecular 5,7-dibrom-8-hydroxy-chinolin. In this case, the acidic sites in mesopores are killed, and the acidic sites in micropores that are smaller than the molecular diameter of 5,7-dibrom-8-hydroxy-chinolin are still active. The cracking of 1,3,5-triisopropylbenzene shows that the treated MAS-7 is still catalytically active. In contrast, the treated MAS-9 and treated Al-SBA-15 are almost inactive. These results show that MAS-7 contains micropores whose size is similar to that of beta. Furthermore, the catalytic cracking of cumene shows that the treated MAS-7 and treated MAS-9 are catalytically active but that the treated Al-SBA-15 is inactive. These results show that MAS-9 also contains micropores whose size is similar to that of ZSM-5. Additionally, the catalytic dehydration of 2-pro...