Question

How would you test the affect of metal salt (activator) on catalase (an enzyme)? What would the procedure look like and what are the materials that would be needed? In this specific lab, ginger and banana extracts are being used as the catalase concentrations.

Answer 1

Enzyme activators are chemical compounds that increase a velocity of enzymatic reaction.The inhibitory effect, and to some extent the stimulation, is salt-specific; the effectiveness of a salt in inhibiting enzyme activity depends on both cation and anion. Thus, the order of effectiveness is MgCl₂ > LiCl > NaCl > KCl > NH₄Cl, and LiCl > LiNO₃ > Li₂SO₄...Stimulation of enzyme activity was observed when one salt was added at its optimal concentration in the presence of inhibiting concentrations of another salt, indicating that the effect on the enzyme is not due to changing water activity but probably to enzyme-salt interaction. Aqueous solutions of ethylene glycol, glycerol, and dimethyl sulfoxide containing no ions influence enzyme activity in the same manner as do salts...Not just the concentration of salt, but also the identity of the ions, and the ionic strength of the solution can affect the activity of an enzyme. It is worth taking the time to try out various salts at a range of concentrations to find the optimal conditions for your enzyme. The same goes for pH.

Material and procedure

Food browning is undesirable as it causes deterioration in food quality and appearance. This phenomenon was related to polyphenol oxidase (PPO), which catalyzes conversion of phenolic compounds into o-quinones...the use of chemical and natural anti-browning agents to prevent the browning of ginger PPO. Sodium metabisulfite (5 mM) is a better chemical inhibitor compared to l-cysteine and sodium chloride as 55.00% of ginger PPO inhibition was achieved. The percentage of inhibition increased as the concentration of anti-browning agents increases. The addition of heated onion, chili pepper and pineapple extracts exhibited a stronger inhibitory effect on ginger PPO than unheated extracts. Heated chili pepper extract was the best natural inhibitor found in this study and it inhibited the ginger PPO (47.97%) mixed-competitively. Natural anti-browning agents have potential to be used to control the browning of ginger as banana .