Some factors that affect the activity of salivary amylase.

I. Objective
To understand the effects of temperature on enzyme activity
to understand the effects of pH on enzyme activity
to understand the effects of activators and inhibitors on enzyme activity
II. Principle The catalytic activity of enzymes is greatly affected by temperature. Enzyme reaction is slower at low temperatures, accelerates as the temperature increases, reaches its maximum temperature, the enzyme reacts fastest, and then slows down as the temperature rises, so as to stop the reaction completely. The activity of salivary amylase increases with the temperature until about 37 degrees C, and the activity of the enzyme decreases when the temperature is higher. In general, when determining the vitality of an enzyme, it is performed at the most appropriate temperature for the enzyme reaction.
It should be noted that the most suitable temperature of an enzyme is not completely fixed, it is related to the length of action, the general action time is long, the most suitable temperature is low, and the action time is short, the most suitable temperature is high. The most suitable temperature of animal enzymes is generally 35 to 40 degrees C, while the most suitable temperature of plant enzymes is higher, between 40 and 50 degrees C.
enzymes are significantly affected by environmental pH. In general, various enzymes only show their activity within a certain pH range. An enzyme that shows the pH at its highest activity is called the most appropriate pH of the enzyme. When below or above the most suitable pH, the activity of the enzyme decreases gradually. Human salivary amylase shows its activity between pH3.8 and 9.4, the most suitable pH is about 6.8.
the most appropriate pH for different enzymes. However, the most suitable pH of the enzyme is affected by the substrate properties and buffer properties. For example, the most appropriate pH for salivary amylase in acetic acid buffer is not 6.8, but 5.6.
activity of enzymes is often affected by certain substances, some of which increase the activity of enzymes, called enzyme activators, and some substances can reduce the activity of enzymes, called enzyme inhibitors.
Cl - is an activator of salivary amylase. Other anions, such as Br-, NO3-and-I, also activate the enzyme, but are weak. Cu2 plus inhibits salivary amylase. The doses of activators and inhibitors that affect enzyme activity are rare and often specific.
in this experiment, diluted saliva was used as amylase. Amylase in saliva gradually hydrolyses starch into dedexion molecules of various sizes, eventually producing maltose and small amounts of glucose. They come in different colors when iodine is encountered. Straight-chain starch (soluble starch) is blue when iodine is present, and in order of molecules from large to small, iodine can be blue, purple, dark brown and red, and the smallest paste and maltose are iodine-free in color:
due to different temperatures, Different pH, or in the presence of activators or inhibitors under the conditions of salivary amylase activity is different, then the degree of starch hydrolyzing is different, so the enzyme reaction mixture can be judged by the color presented by iodine, so as to understand the above factors on enzyme activity. However, it should be noted that iodine under alkaline conditions will be disambiguation reaction, part of iodine formed colorless iodate, secondary iodate, at this time should increase the amount of iodine added.
. Experimental materials and equipment are . 1. Material
saliva
2.
the
water bath boiling water bath ice bath
3. Equipment
ordinary
test tube
: 20mL×8
capacity Bottle: 100mL×1
pipe: 1mL×4 2mL×3 5mL×1
Berred cup: 2 50mL×1 50mL×1
Temperature Meter: 1
Drop tube: 2
Wash Ball: 2 Funnel
,
Bottle
, Test Tube Rack, Pipe Holder, Glass Rod: 1
each.