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Helane?MS?Costa Augusto?CV?Freitas Júnior Ian?PG?Amaral Izaura?Y?Hirata Patrícia?MG?Paiva Luiz?B?CarvalhoJr Vitor?Oliveira Ranilson?S?BezerraEmail author 《Chemistry Central journal》2013,7(1):166
Background
Over the past decades, the economic development and world population growth has led to increased for food demand. Increasing the fish production is considered one of the alternatives to meet the increased food demand, but the processing of fish leads to by-products such as skin, bones and viscera, a source of environmental contamination. Fish viscera have been reported as an important source of digestive proteases with interesting characteristics for biotechnological processes. Thus, the aim of this study was to purify and to characterize a trypsin from the processing by-products of crevalle jack (Caranx hippos) fish.Results
A 27.5 kDa trypsin with N-terminal amino acid sequence IVGGFECTPHVFAYQ was easily purified from the pyloric caeca of the crevalle jack. Its physicochemical and kinetic properties were evaluated using N-α-benzoyl-DL-arginine-p-nitroanilide (BApNA) as substrate. In addition, the effects of various metal ions and specific protease inhibitors on trypsin activity were determined. Optimum pH and temperature were 8.0 and 50°C, respectively. After incubation at 50°C for 30 min the enzyme lost only 20% of its activity. K m , kcat, and k cat /K m values using BApNA as substrate were 0.689 mM, 6.9 s-1, and 10 s-1 mM-1, respectively. High inhibition of trypsin activity was observed after incubation with Cd2+, Al3+, Zn2+, Cu2+, Pb2+, and Hg2+ at 1 mM, revealing high sensitivity of the enzyme to metal ions.Conclusions
Extraction of a thermostable trypsin from by-products of the fishery industry confirms the potential of these materials as an alternative source of these biomolecules. Furthermore, the results suggest that this trypsin-like enzyme presents interesting biotechnological properties for industrial applications.22.
M. Khenfouch R. Minnis Ndimba A. Diallo S. Khamlich M. Hamzah M. S. Dhlamini 《Green Chemistry Letters and Reviews》2016,9(2):122-131
Nowadays graphene is universally known as a promising material. Hence, the development of eco-friendly synthesis methods for this material is of great importance. This study reports on the bio-synthesis of graphene by a green chemistry process using Artemisia herba-alba Asso (AHAA) natural extract. Moreover, this work reports on the physical properties, including surface/interface and optical and electrical properties of the obtained graphene sheets. UV–VIS, Raman, XPS spectroscopies and TEM microscopy investigations confirmed the reduction, and the conversion of graphene oxide to few-layered reduced graphene oxide as well as the efficiency of this plant extract compared with several natural extracts and chemical agents. Furthermore, it was found that the optical and electrical properties of graphene can be modulated and controlled via this eco-friendly cost-effective process. Hence, AHAA can be an effective chelating agent to produce graphene sheets. 相似文献
23.
Sandip N.Gavade Ravi S.Balaskar Madhav S.Mane Pramod N.Pabrekar Murlidhar S.Shingare Dhananjay V.Mane 《中国化学快报》2011,22(6):675-678
The coupling reaction of phenylurea with different functionalized aryl halides in the presence of air stable CuI,N,N-dimethylethylenediamine as a ligand,and K3PO4 as a base gives symmetrical and unsymmetrical diarylureas in relatively high yields.This method is milder than the palladium catalyzed arylation and avoids the use of toxic phosphine ligands. 相似文献
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