Journal of Plant Biochemistry & Physiology
Open Access

An Overview on Mechanism of Enzyme Actions and Influential Factors in Plant Biology

Chave Barinje^{* *}Correspondence: Chave Barinje, Department of Horticulture, National Chung Hsing University, Taichung, Taiwan, Email:

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Description

Enzymes are specialized proteins that act as biological catalysts. They facilitate and accelerate biochemical reactions without being consumed in the process. In plants, enzymes play a vital role in various metabolic pathways, from photosynthesis and respiration to the synthesis of essential molecules such as DNA, RNA, and proteins. These catalysts are important for plant survival, growth, and adaptation to changing environmental conditions.

Enzyme structure

Enzymes typically consist of a three-dimensional structure formed by long chains of amino acids, often folded into a specific shape. This unique configuration is vital for their function. Two essential structural features of enzymes are the active site and the substrate-binding site.

Active site: This is a specific region on the enzyme's surface where the chemical reaction takes place. It has a highly selective and complementary shape that allows it to bind with a particular substrate, the molecule upon which the enzyme acts [1].

Substrate-binding site: The substrate-binding site is where the substrate molecule attaches to the enzyme [2]. This binding is highly specific, and the enzyme recognizes its target substrate through a lock-and-key mechanism. Once the substrate binds to the active site, the enzyme can perform its catalytic effect.

Mechanism of enzyme action

Enzymes work through an accurate and efficient mechanism that can be broadly divided into several steps:

Substrate recognition: Enzymes are highly specific in their action. They recognize their substrate by binding to it, at the active site [3]. This binding ensures that the enzyme acts only on the specific molecule it is considered to interact with.

Formation of the enzyme-substrate complex: The binding of the substrate to the enzyme's active site forms the enzyme substrate complex. This complex is a temporary association that places the substrate in a way that facilitates the chemical reaction.

Catalysis: Once the enzyme and substrate are bound together in the enzyme-substrate complex, the enzyme promotes the conversion of the substrate into products by lowering the activation energy required for the reaction [4]. This acceleration occurs through several mechanisms, including stabilizing transition states and providing an alternative reaction pathway.

Enzyme regeneration: Enzymes are not consumed in the reaction and can be used repeatedly. They return to their original state and are ready to catalyze further reactions once they release the products.

Factors influencing enzyme activity

The efficiency of enzymes in plants is influenced by various factors, including temperature, pH, substrate concentration, and the presence of cofactors and inhibitors.

Temperature: Enzyme activity is highly temperature-dependent. At lower temperatures, enzymes are less active, and the rate of reactions they catalyze is slower [5]. As the temperature increases, enzyme activity typically increases until reaching an ideal temperature. However, if the temperature becomes too high, enzymes can denature, losing their structure and also their function.

pH: Enzymes also have an optimal pH at which they function most effectively. Variations in pH can affect the chemical environment in the active site, affecting the enzyme's ability to bind to the substrate and catalyze the reaction.

Substrate concentration: The rate of an enzymatic reaction often depends on the concentration of the substrate. Initially, increasing substrate concentration results in an increase in reaction rate as more active sites are occupied [6]. However, there is a point at which further increase in substrate concentration do not result to a proportional increase in reaction rate, as all avaliable enzyme active sites are already engaged.

Cofactors and coenzymes: Many enzymes require non-protein molecules called cofactors or coenzymes to function effectively. Cofactors are typically inorganic ions, while coenzymes are small organic molecules [7]. These molecules help in the catalytic process by aiding in substrate binding or facilitating chemical reactions.

Inhibitors: Inhibitors are molecules that can reduce or completely block enzyme activity [8]. There are two main types of inhibitors: Competitive inhibitors, which compete with the substrate for the active site, and non-competitive inhibitors, which bind to a different site on the enzyme, altering its shape and affecting substrate binding.

Examples of enzymes in plant biology

Enzymes play an important role in various plant processes, and numerous examples illustrate their significance in plant biology:

Photosynthesis: The process by which plants convert sunlight into energy involves a series of enzymes, such as Ribulose-1,5- Bisphosphate Carboxylase/Oxygenase (RuBisCO), which is important for carbon fixation [9].

Respiration: Enzymes like ATP synthase and cytochrome c oxidase are involved in energy production and cellular respiration in plants.

DNA replication: Enzymes like DNA polymerase are essential for replicating DNA during cell division and growth.

Defense mechanisms: Plant enzymes like chitinase and protease are involved in defending against pathogens by breaking down cell walls and degrading invading microorganisms [10].

Ethylene production: The enzyme 1-Aminocyclopropane-1- Carboxylate synthase (ACC synthase) is responsible for ethylene production, which regulates various aspects of plant growth and development.

Antioxidant enzymes: Enzymes like superoxide dismutase, catalase, and peroxidase help plants survive oxidative stress and damage caused by reactive oxygen species.

Conclusion

Enzymes play a vital role in the molecular composition of life within every plant cell. Their outstanding specificity, efficiency, and ability to function under a variety of conditions make them central players in plant biology. Understanding the mechanism of enzyme action and the factors that influence their activity is vital not only for scientific research but also for connecting the potential of plants in various agricultural and industrial applications. Enzymes are highly specific, as their active sites only function with specific substrates. Through this mechanism, enzymes play a vital role in regulating and accelerating metabolic processes, making life-sustaining reactions in cells more efficient and selective.

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