ABSTRACT
Starch is composed of glucose units linked by α-1, 4-glucoside bond and α-1, 6-glucoside bond. It is the main component of foods and the primary raw material for starch processing industry. Pullulanase can effectively hydrolyze the α-1, 6-glucoside bond in starch molecules. Combined with other starch processing enzymes, it can effectively improve the starch utilization rate. Therefore, it has been widely used in the starch processing industry. This paper summarized the screening of pullulanase-producing strain and its encoding genes. In addition, the effects of expression elements and fermentation conditions on the production of pullulanase were summarized. Moreover, the progress in crystal structure elucidation and molecular modification of pullulanase was discussed. Lastly, future perspectives on pullulanase research were proposed.
Subject(s)
Glycoside Hydrolases/genetics , Starch/metabolismABSTRACT
The redox biosynthesis system has important applications in green biomanufacturing of chiral compounds. Formate dehydrogenase (FDH) catalyzes the oxidation of formate into carbon dioxide, which is associated with the reduction of NAD(P)+ into NAD(P)H. Due to this property, FDH is used as a crucial enzyme in the redox biosynthesis system for cofactor regeneration. Nevertheless, the application of natural FDH in industrial production is hampered by low catalytic efficiency, poor stability, and inefficient coenzyme utilization. This review summarized the structural characteristics and catalytic mechanism of FDH, as well as the advances in protein engineering of FDHs toward improved enzyme activity, catalytic efficiency, stability and coenzyme preference. The applications of using FDH as a coenzyme regeneration system for green biomanufacturing of chiral compounds were summarized.
Subject(s)
Catalysis , Coenzymes/metabolism , Formate Dehydrogenases/metabolism , NAD/metabolism , Protein EngineeringABSTRACT
Epigallocatechin-3-gallate (EGCG), as one of the main components of green tea, has a variety of biological activities. Both in vitro and in vivo experiments widely demonstrate that EGCG has anticancer activities. The molecular mechanism of EGCG against cancer was much complicated, and EGCG suppressed tumor cell proliferation and/or induced cell apoptosis through multi-pathways. This paper reviewed the anticancer molecular mechanism of EGCG, including EGCG anti-oxidantion, prooxidation, retardant of tumor cell cycle, inhibition of tumor cell angiogenesis, inducement of cancer cell apoptosis, and regulation of microRNA, summarized the research progress of three strategies for improving bioavailability of EGCG: nano-packaging technology, synergistic application and molecular modification, and looked into research and development on anticancer activity of EGCG.
ABSTRACT
ω-Transaminase catalyzes the asymmetric reductive amination of carbonyl compounds, and has great application prospect in the preparation of chiral amines. The application in synthesis of bulky chiral amines is limited by the special structure of substrate binding region in the wild-type enzyme. Moreover, there are also some drawbacks in the stereoselectivity and stability of ω-transaminase. So far, -tωransaminase satisfying the industrial requirements is still rare. In this review, we first introduce the structure and catalytic mechanism of ω-transaminase, and then discuss the structural differences between S-selective and R-selective enzymes. Molecular modification of ω-transaminase was introduced in detail, by focusing on the structure and mechanism-based molecular modification, including substrate specificity, stereoselectivity, and stability.
ABSTRACT
Molecular modification of Chinese materia medica polysaccharides (CMMP) is considered as the technology of modification on some special structure or functional group in the main chain or the side chain of polysaccharides on the purpose of changing certain physicochemical properties and the spatial structure of polysaccharides by using physical, chemical and biological methods which can enhance the biological activity. Physical methods mainly include ultrasonic method and irradiation technology. Chemical methods refer to sulfation, phosphorylation, acetylation, carboxymethylation, alkylation, sulfonylation, selenylation, and so on. Biological method is also called the enzymatic modification containing enzyme degradation and enzymatic synthesis. In recent years, it has been shown that the physicochemical properties and spatial structure of CMMP could be changed after modification, which could make their immunopharmacology activity, such as immune adjustment, antivirus, antitumor, and antioxidant, enhanced obviously. The main modification methods of CMMP and the related pharmacological activity of its products after modification are summarized in this paper.
ABSTRACT
The aim of this paper was to emphasize the importance of prodrug design to therapy, by examining examples available on the Brazilian pharmaceutical market. The principles of prodrug design are briefly discussed herein. Examples of prodrugs from many important therapeutic classes are shown and their advantages relative to the drugs they are derived from are also discussed. Considering the importance of these therapeutic classes, from both therapy and economic standpoints, prodrug design is a very valuable aspect in the research of new drugs and for the pharmaceutical industry as a whole.
O objetivo do trabalho foi ressaltar a importância do planejamento de pró-fármacos para a terapia, por meio de exemplos disponíveis no mercado farmacêutico brasileiro. Os princípios da latenciação são sucintamente discutidos. Apresentam-se exemplos de pró-fármacos de muitas classes terapêuticas importantes e as vantagens relativas aos fármacos dos quais derivam são, também, discutidas. Considerando-se a importância dessas classes terapêuticas, tanto do aspecto terapêutico quanto do econômico, o planejamento de pró-fármacos representa aspecto de grande valor na busca de novos fármacos e na indústria farmacêutica como um todo.
Subject(s)
Drug Synergism , Pharmaceutical Preparations/analysis , Molecular Conformation , Drug Design , Reaction TimeABSTRACT
In recent years,more and more of the enzyme proteins have been carried out using recombinant microorganism bioreactor for large scale production.For reasons of improved the catalytic capability and environmental suitability,or enhanced expression level of the protein,a variety of genetic engineering technology according to protein molecule modification have been applied extensively.Major strategies and achievements of molecular modification for microbial enzyme,such as site-directed mutagenesis,error-prone PCR,DNA shuffling and optimum codon design were reviewed.