生物化学技术

NMR spectroscopy is an extremely valuable and versatile method for studies of nucleosides, nucleotides, and their oligomers. It can provide information about chemical composition, three-dimensional structures, internal motions, and interactions with other macromolecu ...

Gel-capillary electrophoresis is a new alternative to traditional electrophoretic techniques for the analysis of oligonucleotides (1–5). The advantages are dramatically decreased analysis time, excellent resolution, in-capillary detection, reduced sample quantit ...

There are three main analytical methods for determining nucleotide sequences in oligodeoxyribonucleotides. In two of the methods. Mobility Shift Analysis (1,2) and Chemical Cleavage Analysis (4,5), sequences are inferred by visualizing patterns of fragments derived from the ol ...

A biopolymer is synthesized by assembling monomeric or oligomeric blocks. Each block features at least a nucleophilic and an electrophilic function, i.e., the α-amino and the carboxylic functions for peptides, the 5′-OH and the 3′-function (phosphate, phosphoramidite, or phosphonate ...

Methods are described for the laboratory-scale crystallization of “small” organic compounds. The process of crystallization from solution can be used as a purification step in its own right, or to produce crystals for molecular structure determination by single-crystal or powder X-r ...

Isolation of compounds in a pure state from natural sources is the most important, yet can be a difficult and time-consuming, step in natural product research. It begins with the process of extraction followed by various separation techniques. One such separation technique is the solvent par ...

This chapter deals with the isolation of natural products using low-pressure liquid column chromatography (LPLC). A brief summary of the adsorption and size-exclusion processes involved in the LPLC is presented. Different types of stationary phases used in both adsorption and size-e ...

Thin-layer chromatography (TLC) is an easy, cheap, rapid, and widely used method for the analysis and isolation of natural and synthetic products. It has use also in the biological evaluation of organic compounds, particularly in the areas of antimicrobial and antioxidant metabolites, and ...

Supercritical fluids (SCFs) are increasingly replacing organic solvents, e.g., n-hexane, dichloromethane, chloroform, and so on, that are conventionally used in industrial extraction, purification, and recrystallization operations because of regulatory and environme ...

Currently, there is a growing interest in the study of natural products, especially as part of drug discovery programs. Secondary metabolites can be extracted from a variety of natural sources, including plants, microbes, marine animals, insects, and amphibia. This chapter focuses prin ...

There has been a remarkable resurgence of interest in natural product research over the last decade or so. With the outstanding developments in the areas of separation science, spectroscopic techniques, and microplate-based ultrasensitive in vitro assays, natural product resear ...

Scale-up of natural product isolation involves not only an increase in the scale of the purification of the target compound but also an improved level or scale in its production. As the scale increases, efficiency of operation becomes more important, necessitating process development. The ...

Microbial fermentations conducted with the express purpose to generate organic molecules are invariably carried out in a liquid medium, and the organic components produced can be distributed between both the solid and liquid phases. A major challenge facing the practitioner attemp ...

Plant secondary metabolites are currently the subject of much research interest, but their extraction as part of phytochemical or biological investigations presents specific challenges that must be addressed throughout the solvent extraction process. Successful extract ...

This review summarizes the advances in dereplication technology since 1998, its current status, and the prospects for future development. Developments are being driven by the need to identify novel pharmaceutical and agrochemical lead compounds rapidly and effectively from com ...

The technique developed from the coupling of a separation technique and an on-line spectroscopic detection technology is known as hyphenated technique. The remarkable improvements in hyphenated analytical methods over the last two decades have significantly broadened their a ...

Preparative high-performance liquid chromatography (HPLC) has become a mainstay of natural product isolation and purification. The various modes available (e.g., normal-phase, reversed-phase, size exclusion, and ion-exchange) to date can be used to purify most classes of natural ...

The rapid development of the small interfering ribonucleic acid (siRNA)-induced inhibition of the gene expression at the RNA level offers to research groups a new strategy for the understanding of gene functions. The siRNA approach is close to antisense oligonucleotide technology and ...

In vitro selection or systematic evolution of ligands by exponential enrichment is a combinatorial procedure that allows the identification of oligonucleotides showing properties of interest—so-called aptamers—through iterative selection/amplification rounds. ...

Since the early 1990s, combinatorial deoxyribonucleic acid and ribonucleic acid libraries have been used to isolate specific ligands for a variety of target molecules, as well as nucleic acid-based catalysts for different reactions. These iterative procedures are based on the fact th ...