Evolutionary History of Plant Lipolytic Enzymes

The discovery of enzymes with lipolytic activities in all kingdoms of life from prokaryote to eukaryote species raises the possibility of the presence of an evolutionary relationship history of these proteins among many species of various living organisms. The chapter suggests a strategy based on the phylogenetic distribution and homology conservation in plant lipolytic enzymes for possible depiction of their biological evolution. Extensive databases and online resources for lipidomics and related areas are useful tools to analyze the different lipolytic enzymes in the three major super kingdoms of life, including higher plants kingdom and confined organisms such as algae that have recently gained much interest due to their promising potential applications in lipids hydrolysis and biosynthesis. Multiple sequence alignments of the identified lipolytic enzymes from databases could serve to the identification of globally conserved residues as well as conserved sequence motifs. Estimation of evolutionary distance between the various identified lipolytic enzymes could also be carried out to better understand the pattern of evolution.

Plant Lipases

Most searches in plant lipases have been devoted to seed lipases, but other sources of plant lipases are being exploited. The current chapter is undertaken to show readily available sources of lipases from plants as well as for their biochemical properties and some of their other eminent characteristics. The sequence and structural characterization into these lipolytic enzymes as well as their importance for biotechnological applications would also be the focus of this chapter. In fact, plant lipases have interesting features, particularly biochemical properties (e.g., pH and temperature), and with respect to their specific hydrolytic properties would make these enzymes alternative remedies for treatment of many diseases of the gastrointestinal tract and of pancreatic insufficiency with exogenous plant acid stable lipases.

Plant Lipases and Phospholipases and Their Diverse Functions and Applications

Lipases and phospholipases from plants have very interesting features for potential functions and applications in different fields. Plant lipases and phospholipases are ubiquitous proteins found either in basic or higher organs of plants. This chapter provides an overview of the diverse functions of these enzymes. The chapter addresses the issue of the importance regarding the functions of plant lipolytic enzymes (i.e., lipases and phospholipases) and their different forms not only for plants but also for external applications. The commercial exploitation of such plant proteins as industrial enzymes would be made as a potentially attractive alternative. The applications of plant lipases and phospholipases in biotechnology and industry such of food, detergents, effluent treatment, biodiesel production, as well as medicines and nutraceuticals are reviewed.

Plant Lipolytic Enzymes

The main plant lipolytic enzymes discussed in this chapter are hydrolases that catalyze neutral lipids (non-polar lipids), that is, lipases or those hydrolyzing polar lipids, for example, phospholipases (A, C, and D) as well as those of related field like diacylglycerol kinases, lipoprotein lipases, lipid phosphate phosphatases, and lysophospholipases. This chapter provides generalities regarding some important aspects of plant lipolytic enzymes from either higher plants or algae, such as sources, reactions catalyzed, and specificities. Major issues for purification of plant enzymes with lipolytic activities are highlighted in this overview. New insights into implementation of relevant proteomic and lipidomic techniques to identify and characterize plant lipolytic enzymes with the aid of internet resources are also reviewed in this chapter.

Plant Phospholipases D

Studying phospholipases D (PLDs) from plants is very interesting as these enzymes might play important roles in many processes. PLDs are thought to cleave the phosphodiesteric bonds of the head group of phospholipids. The structure and function of oat (Avena sativa) PLD remain poorly understood, and their properties need to be further elucidated. In the chapter, functional proteomics and bioinformatic approaches were used to identify and characterize isoforms of oat PLD. Insights into structural characterization of oat predicted isozymes were analyzed using in silico approaches. Primary structures were analyzed, and a phylogeny analysis and protein motif/domain identification were presented. A multiple sequence alignment of the putative oat PLD revealed consensus sequences with the well-known important putative catalytic residues characterized by such enzymes. The results here provide a detailed view of the main residues involved in catalysis in this kind of enzyme.

Plant Phospholipases C

Plant phospholipases C (PLCs) that hydrolyze the phosphodiesteric linkages of the head group of phospholipids can be grouped into three major types—non-specific PLC (NPC), phosphoinositide-specific PLC (PI-PLC), and glycosylphosphatidylinositol (GPI)-PLC—according to the specificity of substrate and the cellular functions. After an overview of the main features in these plant enzymes, a case study of oat (Avena sativa) PI-PLCs isoforms is presented in this chapter to highlight insights into structure characterization of such predicted isozymes. Although oat PI-PLCs could not be purified to homogeneity due to their association with other proteins, particularly the actin cytoskeleton, the intended enzymes could be identified, analyzed, and characterized by functional proteomics, bioinformatics, and in silico approaches. In this chapter, sequence and structure analyses, as well as phylogenetic evolution of the predicted oat PI-PLCs, were reported to show the specific motifs and the main putative catalytic residues characteristics of such plant enzymes.