Preface

Since its invention by the Russian botanist Mikhail Semyonovich Tsvet in 1901 [1], chromatography has evolved into a flexible analytical technique of which there are many permutations with various applications both in academia and industry, and is considered the most versatile of all methods of chemical analysis. Chromatography is used in the separation of compounds according to their distribution between two phases. The compound mixture is dissolved in a fluid known as *mobile phase,* which carries it through a structure holding another material known as *stationary phase*. The various constituents of the compound mixture travel at different speeds due to differences in the compound's partition coefficient which allows the separation based on differential partitioning between the two phases resulting in differential retention on the stationary phase, thus performing the separation. Nowadays, the use of chromatography is associated with a wide range of detection systems, including electrochemical, photometric and mass spectrometry, and plays a vital role in the advancement of science. The authors of *Chromatography - the Most Versatile Method of Chemical Analysis* have contributed chapters which focus on purification, analysis, models, retention parameters and sample preparation with different applications in biotechnology, ecology, environment, food and toxicology. Finally, I am most happy to have received contributions from internationally renowned contributors from different parts of the world join us to report on their traditional and innovative approaches, as well as reviews of the most relevant and impacting aspects of chromatography. I hope that readers of this book will find new ideas, approaches and inspiration to solve separation problems. Finally, I would like to thank all the authors and Mr. Oliver Kurelic for their contributions and their cooperation throughout the previous year.

#### **Leonardo de Azevedo Calderon**

Centro de Estudos de Biomoléculas Aplicadas a Saúde Universidade Federal de Rondônia Fundação Oswaldo Cruz , Porto Velho, Brazil

[1] Heftmann, E. (1983). History of chromatography and electrophoresis. *Journal of Chromatography Library* 22(A): A19–A26. http://dx.doi.org/10.1016/S0301-4770(08)60863-5

**Chapter 1** 

© 2012 Calderon et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2012 Calderon et al., licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**Purification of Phospholipases A2**

Rodrigo G. Stábeli, Rodrigo Simões-Silva, Anderson M. Kayano, Gizeli S. Gimenez, Andrea A. Moura, Cleópatra A. S. Caldeira, Antonio Coutinho-Neto, Kayena D. Zaqueo, Juliana P. Zuliani,

Snake venoms are a complex mixture of compounds with a wide range of biological and pharmacological activities, which more than 90% of their dry weight is composed by proteins, comprising a variety of enzymes, such as proteases (metalo and serine), phospholipases A2, L-aminoacid oxidases, esterases, and others [1-5]. A great number of proteins were purified and characterized from snake venoms [1, 2]. Some of these proteins exhibit enzymatic activity, while many others are non-enzymatic proteins and peptides. Based on their structures, they can be grouped into a small number of super-families based on remarkable similarities in their primary, secondary and tertiary structures, however

One of the most important protein super-families present in snake venoms are the phospholipases A2 (PLA2, E.C. 3.1.1.4), a class of heat-stable and highly homologous enzymes, which catalyse the hydrolysis of the 2-acyl bond of cell membrane phospholipids releasing arachidonic acid and lysophospholipids (Figure 1). These proteins are found in a wide range of cells, tissues and biological fluids, such as macrophages, platelets, spleen, smooth muscle, placenta, synovial fluid, inflammatory exudate and animal venoms. There is a high medical and scientific interest in these enzymes due to their involvement in a variety of inflammatory diseases and accidents caused by venomous animals. Since the first PLA2 activity was observed in Naja snake venom, PLA2s were characterized as the major component of snake venoms, being responsible for several pathophysiological effects caused by snake envenomation, such as neurotoxic, cardiotoxic, myotoxic, cytotoxic, hypotensive

**from American Snake Venoms** 

Leonardo A. Calderon and Andreimar M. Soares

Additional information is available at the end of the chapter

showing distinct pharmacologic effects [3].

and anti-coagulant activities [1-10].

http://dx.doi.org/10.5772/53052

**1. Introduction** 
