@article {769,
	title = {Enzymatic characterization and functional groups of polyphenol oxidase from the pupae of blowfly (Sarcophaga bullata)},
	volume = {69},
	year = {Submitted},
	note = {08-10-200906-02-2012NormalKey Laboratory of Ministry of Education for Cell Biology and Tumor Cell Engineering, School of Life Sciences, Xiamen University, Xiamen, 361005, China.enghttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve\&db=pubmed\&dopt=Abstract\&list_uids=15377273},
	pages = {918 - 920},
	publisher = {Copyright 2004 MAIK},
	abstract = {Polyphenol oxidase (EC 1.14.18.1) was purified from the pupae of blowfly (Sarcophaga bullata) by a procedure involving ammonium sulfate fractionation and chromatography on DEAE-cellulose and Sephadex G-100. Kinetic characteristics of the enzyme were determined using L-DOPA as substrate. The specific activity of the enzyme was 770 U/mg, and the Michaelis constant (Km) was 1.5 +/- 0.1 mM (pH 6.8, 30 degrees C). Activity was maximal at 40 degrees C, pH 6.5. Chemical modification experiments demonstrated that cysteine and tryptophan residues are essential and arginine residues are not essential to the enzyme function. The enzyme is inhibited by quercetin with an IC50 of 0.20 +/- 0.06 mM. The inhibition is of competitive type, and the inhibition constant was determined to be 88 micro M.},
	keywords = {Animals, Catechol Oxidase/antagonists \&amp, Diptera/*enzymology, Hydrogen-Ion Concentration, inhibitors/*chemistry/*metabolism, Inhibitory Concentration 50, Kinetics, Pupa/*enzymology, Quercetin/pharmacology, Structure-Activity Relationship},
	author = {Wang, Q. and Chen, Q. X. and Huang, X. H. and Ke, L. N. and Shi, Y. and Wang, J.}
}
@article {293,
	title = {Inactivation Kinetics of Polyphenol Oxidase from Pupae of Blowfly (Sarcophaga bullata) in the Dimethyl Sulfoxide Solution},
	year = {Submitted},
	note = {08-10-200906-02-2012NormalCollege of Urban and Environmental Sciences, Peking University, Peking, 100871, China.ENGhttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve\&db=pubmed\&dopt=Abstract\&list_uids=19669602},
	abstract = {The effects of dimethyl sulfoxide (DMSO) on the activity of polyphenol oxidase (PPO, EC 1.14.18.1) from blowfly pupae for the oxidation of L: -3,4-dihydroxyphenylalanine were studied. The results showed that low concentrations of DMSO could lead to reversible inactivation to the enzyme. The IC(50) value, the inactivator concentration leading to 50\% activity lost, was estimated to be 2.35 M. Inactivation of the enzyme by DMSO was classified as mixed type. The kinetics of inactivation of PPO from blowfly pupae in the low concentrations of DMSO solution was studied using the kinetic method of the substrate reaction. The rate constants of inactivation were determined. The results show that k (+0) was much larger than [Formula: see text], indicating that the free enzyme molecule was more fragile than the enzyme-substrate complex in the DMSO solution. It was suggested that the presence of the substrate offers marked protection of this enzyme against inactivation by DMSO.},
	author = {Chen, C. Q. and Li, Z. C. and Pan, Z. Z. and Zhu, Y. J. and Yan, R. R. and Wang, Q. and Yan, J. H. and Chen, Q. X.}
}
