Chemical Reactions in Living Organisms: Enzymes - Coursework Example

An enzyme is an organic molecule that acts as a catalyst for many biological reactions. Most are protein in nature but some are RNA in nature. They are highly specific and sensitive (Klaus Buchholz, 2012) to the substrates and conditions in which they function. b) Explain two similarities and two differences between the way an enzyme works on one hand and an inorganic catalyst on the other.

Similarities; Both an enzyme and an inorganic catalyst work by reducing the activation energy (Gibbs energy) (Thermodynamics, 2013)required to facilitate a reaction. Both an enzyme and an inorganic catalyst are also sensitive to conditions in a reaction. For example, most enzymes are sensitive to pH and temperature. The same is true for some catalysts such as manganese salts that are pH sensitive and heat sensitive, requiring controlled conditions to work. (Klaus Buchholz, 2012)Both enzymes and catalysts also have positive and negative catalysis.

Enzymes are either activators or inhibitors, while the inorganics are either negative or positive catalysts. Differences; Enzymes are organic, containing protein sub-groups. As such they are high molecular weight compounds. Inorganic catalysts are often low molecular weight. Inorganic catalysts are more resilient to changes in temperatures. An example is Pt/Rh catalysts used at high temperatures. This is compared to organic catalysts that denature past a certain temperature (mostly 40 degrees Celsius).

Enzymes are also manufactured by biological systems, and as such most are highly specific to the reactions and substrates they require for such. Inorganic catalysts are sometimes ambiguous. Thcatalyzeyse numerous reactions as long as the conditions are right. For example Platinum, Pt is a catalyst for a wide range of industrial processes. Enzymes are also several times faster in their catalyzing of reactions compared to organocatalyst levelvel 3 (Assessment Criterion 3.2)Q2 There are two main concepts regarding the mechanisms of enzyme specificity. a) Name and explain one of these theories.

Lock and key model- this model was proposed by EFischercher. It states that an enzyme is like a lock, while a substrate is like a key. As such, an enzyme can only be bound by a specific type of substrate (Spencer Seager, 2013) and this means that for any given enzyme, the substrate has to be specific or highly similar to the substrate for the reaction to occur. This model/ theory shows the enzyme as conformationally rigid and able to only act on substrates that are an exact fit. (Timberlake, 2014)b) Name and explain the other theory of enzyme specificity.

Koshland’s induced fit theory- this theory states that an enzyme is not a rigid structure. As a substrate binds, it leads s to a conformational change that enhancesenzyme'szymes ability to carry out its catalytic function. In some,casesenzyme'szymes active sitremoldedulded completely and the charge of the enzyme is also modified as it binds to its substrate. (Spencer Seager, 2013) After catalysis has been carried out, the enzyme resumes its original shape. (Timberlake, 2014)Level 3 (Assessment Criterion 3.3)Q3 You are an investigator and your research group has just isolated two novel enzymes A and B that are both secreted into the small intestine of the domestic pig Sus scrofa.