آی اس آی پیپر

دانلود رایکان مقاله انگلیسی ISI با موضوع پروکسیداز خام از ضایعات جامد پیاز همانند ابزاری برای سنتز ارگانیک

عنوان فارسی مقاله:

پروکسیداز خام از ضایعات جامد پیاز همانند ابزاری برای سنتز ارگانیک. بخش اول: حلقه ای شدن پنتاهیدروکسی – چالکون 2,3,4,4,6 درون آئوروسیدین

عنوان انگلیسی مقاله:

Crude peroxidase from onion solid waste as a tool for organic synthesis. Part I: Cyclization of 20 ,3,4,40 ,60 -pentahydroxy-chalcone into aureusidin

دانلود رایگان مقاله ISI با فرمت PDF:

مشاهده توضیحات کامل و خرید ترجمه فارسی با فرمت ورد تایپ شده:

بخشی از مقاله انگلیسی :

A blank reaction was carried out under the same conditions and concentrations, but with the exclusion of enzymic extract. The reaction was monitored by LC-DAD-MS and formation of the aureusidin aurone ring was not observed. Moreover, as is postulated in the work of Detsi et al.,8 the oxidative cyclization of chalcones into aurones can be achieved under harsh reaction conditions, involving the use of metal salts, strongly acidic or basic reagents, and heating. It important to mention that, although PHC is not a natural substrate for the onion POD as known to date,31 this methodology allows it to be cyclized exclusively into aureusidin, thus it can be postulated that this crude enzyme preparation manifests an as yet uncharacterized PPO activity. On the other hand, cyclization of PHC using a crude Aureusidin synthase extract from yellow snapdragon flowers has been reported to produce aureusidin/bracteatin in a ratio of 6:1.19 This study proved that onion POD can mimic AS (a PPO analogue) as far as the oxidative cyclization of PHC is concerned.