Current Protein and Peptide Science - Volume 12, Issue 5, 2011

Plant protease inhibitors (PIs) continue to exert interest among plant biochemists and biotechnologists in spite of the (almost complete) failure in the production of transgenic crops with enhanced resistance toward insects. Indeed, plant PIs still offer an ample space for both applicative and basic researches. The huge reservoir provided by the Plant Kingdom, the development of investigative methodologies and biotechnologi Read More

This review outlines known examples of the three-dimensional structures of protein proteinase inhibitors from plants. Three families of enzymes, serine proteinases, carboxypeptidases and cysteine proteinases, are targeted by at least a dozen inhibitor families, with the majority of them adopting the standard mechanism of inhibition towards the serine proteinases. All of the inhibitors discussed maintain compact and stab Read More

Seed proteins that inhibit proteinases are classified in families based on amino acid sequence similarity, nature of reactive site and mechanism of action, and are used as tools for investigating proteinases in physiological and pathological events. More recently, the plant Kunitz family of inhibitors with two disulphide bridges was enlarged with members containing variable number of cysteine residues, ranging from no cyst Read More

Bowman-Birk inhibitors and their variants (BBI) from legumes, such as soybean, pea, lentil and chickpea, are a class of naturally-occurring protease inhibitors which have potential health-promoting properties within the gastrointestinal tract. BBI can resist both acidic conditions and the action of proteolytic enzymes, and transit through the stomach and small intestine without major degradation, permitting significant amounts to r Read More

Serine protease inhibitors (PIs) are a large and complex group of plant proteins. Members of the Potato type I (Pin1) and II (Pin2) proteinase inhibitor families are among the first and most extensively characterized plant PIs. Many insects and phytopathogenic microorganisms use intracellular and extracellular serine proteases playing important roles in pathogenesis. Plants, however, are able to fight these pathoge Read More

Plant protease inhibitors (PIs) are generally small proteins present in high concentrations in storage tissues (tubers and seeds), and to a lower level in leaves. Even if most of them are active against serine and cysteine proteases, PIs active against aspartic proteases and carboxypeptidases have also been identified. Inhibitors of serine proteases are further classifiable in several families on the basis of their structural features. The Read More

Systemin, an 18-amino acid signaling peptide isolated from tomato leaves, has been found to be an integral component of the jasmonic acid signaling pathway, leading to the synthesis of protease inhibitors (PIs). The discovery of systemin has led to a search for other peptide signals involved in defense in the Solanaceae and in other plant families. A new class of peptides having similar signaling properties but little se Read More

Proteinase inhibitors which act on the digestive enzymes of insect herbivores are a basic mechanism of plant defence. Attempts to exploit this defence mechanism in plant genetic engineering have used over-expression of both endogenous and exogenous inhibitors. While significant protection against insect pests has been routinely achieved, the engineered plants do not show levels of resistance considered commer Read More

Proteinases play a fundamental metabolic role during the life cycle in the plant kingdom. By interacting with endogenous or exogenous inhibitors, the proteolytic activity is modulated to meet metabolic requirements. By probing proteolytic enzymes with their inhibitors, it is possible to identify novel functions unrelated to their proteolytic activity. A group of plant proteolytic enzymes stands as a line of defence against environm Read More

Plants are at the basis of the food chain, but there is no such thing as a “free lunch” for herbivores. To promote reproductive success, plants evolved multi-layered defensive tactics to avoid or discourage herbivory. To the detriment of plants, herbivores, in turn, evolved intricate strategies to find, eat, and successfully digest essential plant parts to raise their own offspring. In this battle the digestive tract is the arena determi Read More

PlantPIs is a web querying system for a database collection of plant protease inhibitors data. Protease inhibitors in plants are naturally occurring proteins that inhibit the function of endogenous and exogenous proteases. In this paper the design and development of a web framework providing a clear and very flexible way of querying plant protease inhibitors data is reported. The web resource is based on a relational database, Read More