Polyphenol oxidase （PPO） is the enzyme responsible for enzymatic browning during the growth of insects. It is also involved in defense reactions and is related with immunities in insects. PPO a metalloenzyme oxidase...Polyphenol oxidase （PPO） is the enzyme responsible for enzymatic browning during the growth of insects. It is also involved in defense reactions and is related with immunities in insects. PPO a metalloenzyme oxidase, catalyzes the oxidation of o-diphenol to o-quinone. The present paper describes the effects of benzaldehyde and its p-substituted derivatives on the activity of PPO from the fifth instar of Pieris rapae L. PPO from the fifth instar of Pieris rapae L. was purified using ammonium sulfate fractionation and chromatography on Sephadex G-100. The enzyme kinetics was characterized using L-3,4-dihydroxyphenylalanine （L-DOPA） as substrate. The results show that benzaldehyde, phydroxybenzaldehyde, p-chlorobenzaldehyde, and p-cyanobenzaldehyde can inhibit the PPO activity for the oxidation of L-DOPA. The inhibitor concentration leading to 50% activity lost, IC50, was estimated to be 5.90, 5.62, 2.83, and 2.91 mmol/L for the four tested inhibitors, respectively. Kinetic analyses show that the inhibitory effects of these compounds are reversible. Benzaldehyde, phydroxybenzaldehyde, and p-chlorobenzaldehyde are noncompetitive inhibitors while p-cyanobenzaldehyde is a mixed-type inhibitor. The inhibition constants were determined for all four inhibitors. p-chlorobenzaldehyde and p-cyanobenzaldehyde were more potent inhibitors than the other compounds. These results provide a basis for developing PPO inhibition-based pesticides.展开更多
Synthesis and insecticidal activity of α substituted (3 phenoxy) benzaldehyde O (methyl carbamoyl) oxime were studied.The products were characterized by IR, 1HNMR and elemental analysis.The experimental findings of i...Synthesis and insecticidal activity of α substituted (3 phenoxy) benzaldehyde O (methyl carbamoyl) oxime were studied.The products were characterized by IR, 1HNMR and elemental analysis.The experimental findings of insecticidal activity demonstrated that these compounds have the notable effect on the Aphis medicaginis Koch.展开更多
The kinetic behaviors of Wittig Horner reaction between α naphthylmethyl dibutyl phosphate and substituted benzaldehydes have been investigated.The mechanism of the reaction is discussed on the basis of the rate cons...The kinetic behaviors of Wittig Horner reaction between α naphthylmethyl dibutyl phosphate and substituted benzaldehydes have been investigated.The mechanism of the reaction is discussed on the basis of the rate constant k,Hammett ρ,correlative coefficient r,ΔS ≠.The yields of the competing reactions between benzaldehyde and p nitrobenzaldehyde and lihewis studied by the way..展开更多
二氯二茂钛与取代苯甲醛肟钠在二氯甲烷中反应,生成二茂钛单肟衍生物 Cp_2TiCl(ON=CHAr),其中 Ar 为邻硝基苯基、间硝基苯基、对硝基苯基、邻氯苯基、间氯苯基、3,4-二氯苯基、间甲氧基苯基、对甲氧基苯基、2,4-二甲氧基苯基和3,4-亚甲...二氯二茂钛与取代苯甲醛肟钠在二氯甲烷中反应,生成二茂钛单肟衍生物 Cp_2TiCl(ON=CHAr),其中 Ar 为邻硝基苯基、间硝基苯基、对硝基苯基、邻氯苯基、间氯苯基、3,4-二氯苯基、间甲氧基苯基、对甲氧基苯基、2,4-二甲氧基苯基和3,4-亚甲基二氧苯基。所有这些新化合物在干燥空气中稳定,对潮湿空气敏感.经元素分析和红外、核磁氢谱表征,确认了其结构。展开更多
基金Supported by the Science and Technology Foundation of Fujian Province (No. 2004N002)the National Natural Science Foundation of China (No. 30570408)
文摘Polyphenol oxidase （PPO） is the enzyme responsible for enzymatic browning during the growth of insects. It is also involved in defense reactions and is related with immunities in insects. PPO a metalloenzyme oxidase, catalyzes the oxidation of o-diphenol to o-quinone. The present paper describes the effects of benzaldehyde and its p-substituted derivatives on the activity of PPO from the fifth instar of Pieris rapae L. PPO from the fifth instar of Pieris rapae L. was purified using ammonium sulfate fractionation and chromatography on Sephadex G-100. The enzyme kinetics was characterized using L-3,4-dihydroxyphenylalanine （L-DOPA） as substrate. The results show that benzaldehyde, phydroxybenzaldehyde, p-chlorobenzaldehyde, and p-cyanobenzaldehyde can inhibit the PPO activity for the oxidation of L-DOPA. The inhibitor concentration leading to 50% activity lost, IC50, was estimated to be 5.90, 5.62, 2.83, and 2.91 mmol/L for the four tested inhibitors, respectively. Kinetic analyses show that the inhibitory effects of these compounds are reversible. Benzaldehyde, phydroxybenzaldehyde, and p-chlorobenzaldehyde are noncompetitive inhibitors while p-cyanobenzaldehyde is a mixed-type inhibitor. The inhibition constants were determined for all four inhibitors. p-chlorobenzaldehyde and p-cyanobenzaldehyde were more potent inhibitors than the other compounds. These results provide a basis for developing PPO inhibition-based pesticides.
文摘Synthesis and insecticidal activity of α substituted (3 phenoxy) benzaldehyde O (methyl carbamoyl) oxime were studied.The products were characterized by IR, 1HNMR and elemental analysis.The experimental findings of insecticidal activity demonstrated that these compounds have the notable effect on the Aphis medicaginis Koch.
文摘The kinetic behaviors of Wittig Horner reaction between α naphthylmethyl dibutyl phosphate and substituted benzaldehydes have been investigated.The mechanism of the reaction is discussed on the basis of the rate constant k,Hammett ρ,correlative coefficient r,ΔS ≠.The yields of the competing reactions between benzaldehyde and p nitrobenzaldehyde and lihewis studied by the way..
文摘二氯二茂钛与取代苯甲醛肟钠在二氯甲烷中反应,生成二茂钛单肟衍生物 Cp_2TiCl(ON=CHAr),其中 Ar 为邻硝基苯基、间硝基苯基、对硝基苯基、邻氯苯基、间氯苯基、3,4-二氯苯基、间甲氧基苯基、对甲氧基苯基、2,4-二甲氧基苯基和3,4-亚甲基二氧苯基。所有这些新化合物在干燥空气中稳定,对潮湿空气敏感.经元素分析和红外、核磁氢谱表征,确认了其结构。
