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Il complesso produce la reazione, ma dopo la nascita del prodotto di reazione l'enzima può essere nuovamente riutilizzato.
== PropertiesProprietà ofdegli Enzymesenzimi ==
1. Gli enzimi sono sensibili al calore , e possono essere danneggiati (il termine chimico corretto è '''denaturati''') facilmente per eccesso di freddo o di caldo.Queste due cause possono modificare irreparabilmente il sito attivo : danneggiando il sito attivo non si forma il complesso enzima-substrato.
1. Enzymes are sensitive to heat, and are denatured by excess heat or cold, i.e. their active site becomes permanently warped, thus the enzyme is unable to form an enzyme substrate complex. This is what happens when you fry an egg, the egg white (augmenten, a type of protein, not an enzyme), is denatured.
2. Gli enzimi sono creati nelle cellule ma sono capaci di funzionare anche fuori di essa.Questo consente agli enzimi di essere immobilizzati senza distruggerli.
2. Enzymes are created in cells but are capable of functioning outside of the cell. This allows the enzymes to be immobilised, without ''killing'' them.
3. Gli enzimi sono sensibili al pH, il tasso al quale possono condurre una reazione è dipendente dal PH .Un esempio è la '''pepsina''' che funziona in presenza di PH vicino a 2. Invece l'amilasi salivare raggiunge il massimo rendimento con un PH neutro, cioè vicino a 7.
3. Enzymes are sensitive to pH, the rate at which they can conduct reaction is dependent upon the pH of where the reaction is taking place, eg pepsin in the stomach has an optimum pH of about pH2. Whereas salivary amylase has an optimum pH of about 7.
4. Gli enzimi sono riutilizzabili ed alcuni enzimi sono capaci di catalizzare centinaia di migliaia di reazioni ogni secondo.
4. Enzymes are reusable, and some enzymes are capable of catalysing many hundreds of thousands of reactions every second, e.g. catalase working on hydrogen peroxide.
5. Ogni enzima è specifico cioè può catalizzare una sola reazione.
5. Enzymes will only catalyse one reaction, e.g. invertase will only produce glucose and fructose, when a glucose solution is passed over beads of enzyme (see Immobilisation).
6. Gli enzimi lavorano anche in modo da raggiungere la quantità desiderata e mai in eccesso: quando si forma uneccesso di composto, smettono di produrlo fino ache il sistema non è tornato in equilibrio.
6. Enzymes are capable of working in reverse, this acts as a cut off point for the ammount of product being produced. If there are excess reactants the reaction will keep going and be reversed, so that there is no overload or build up of product.
Enzymes may be immobilised in two ways, firstly by bonding them chemically to some sort of rigid structure, and secondly by physically placing the enzymes on an insolube support structure, eg a gel or bead. The second method of enzyme immobilisation is much more common, is cheaper, but it does reduce the enzyme's ability to catalyse reactions.
'''Steps in Enzyme immobilization'''
1. Make up a 5% w/v solution of sodium alginate, and leave to stand overnight, to mix properly.
2. Add the enzyme, or in this case, a cell eg yeast, to the alginate solution, and mix in well. At this point the mixture will be very thick, and should be left for twenty minutes to eliminate the air bubbles, from the solution; such air bubbles would increase the surface area of the beads, making them less efficent.
3. Take a syringe, and fill it with the alginate/cell matrix.
4. Make a 2% w/v solution of Calcium Chloride.
5. Hold the syringe about 20 cm perpendicularly above the calcium chloride solution, and drip in the alginate solution, trying to create the smallest possible beads, approx 3-4mm in diameter.
6. Remove and discard any alginate strings or floating beads from the chloride solution.
7. Rinse the beads in deionised water.
8. Using a retort stand set up two tap funnels above each other, placing the beads in the bottom funnel, and strong glucose in the top.
9. Allow the glucose to run through the beads, and draw off the product.
The product is a type of alcohol, which should not be ingested as it is impossible to tell whether it is ethanol or methanol, the later being toxic.
== Naming Enzymes==
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