RATIFICATION PAGE

Complete report of Basic Biology practicum with title “The Influence of pH

on enzyme activities’’ that arranged by :

Name : Jeny Ayu Hardiah Ningrum

Registrasion Number : 1114040162

Group : III (Three)

Class : ICP A

After checked by Assistant and Assistant Coordinator so this report was

accepted.

Makassar, November 26th 2011

Assistant Coordinator Assistant

(Djumarirmanto, S.Pd) (Engka Rukmana) ID. 091404173

CHAPTER IINTRODUCTION

A. Background

This is one of kinds of the subject and chemistry, this subject is not of

new word for me because we have hot it in junior high school, senior high

scool and now in university. this word is enzyme, we have known if were

living thing and we have known also about all substance in the word. Ther are

alements and compounds, and we would try to discussed about compounds.

Enzyme is one of the kinds catalisator and compounds, we have

known about the meaning, the function and advantage of enzyme, that are all

we have got in the pas time before we done this practicum, so that we must to

easy to done this practicum learn about enzyme.

This practicum also discussed about pH, and us we know that if pH is

one of the way to know the activity of enzyme amilaze, so that if we want to

known the activity of enzyme we must to known about pH before practicum,

pH is manner to known the condition of solution are acid od bases, most of

what we known about how enzymes work is gained from studying them in

vitro, usually one isolated test at a time, but a living cell may have the

potencial for many thousands of tests, so it is immediately evident. The major

task of metabolism is provided energy for the maintenance of life, this is

accomplished by degrading chemical compounds of relatively high potential

energy to products of low potential energy.

So that to known about pH and enzyme in this practicum, to known

about function of pH and enzymes in this practicum, and to known about the

advantage of pHand enzynein this practicum, we must to done this practicum

seriously, but if don’t seriously we we will do fault,as insert material excess,

and result that at wants not also as one of original.

B. Purpose

To prove the effect of pH on enzyme activity.

C. Benefit

Student at university could know proved the effect of pH of enzyme amilaze.

CHAPTER IIPREVIEW OF LITERATURE

Enzymes can be found in both animals and plants, One of the enzymes

contained in plants is amilaze, another name of amilaze is diastase. The enzyme

can hydrolyze starch to sugar, amilaze produced by the leaves or seeds are

germinated. Amilaze activity is affected by inorganic salts, pH, temperature, light,

pH optimum of amilaze according to Hopkins, Cole and green (Miler, 1983) is 4,5 to

4,7 (Tim Pengajar, 2011).

One of the distinguishing characteristics of living organisms is the presence

within them of the special catalysts called enzymes. The existence of these catalysts

in living tissues accounts for the rapid execution and control of an exceedingly large

number of biochemical tests. Enzymes posses all the properties we have noted for

catalysts in general. The speed up tests that are otherwise so slow that they would

virtually never occur: the are not consumed in the tests and in small e amounts

perform much work. In addition, they mentioned. Although enxymes are produced

only by living organisms, they may be sprout extracted from tissues, purified,

crystallized, and studied in isolation. Through such studies, the knowledge of

enzymes and their catalytic properties has expanded dramatically in the last two

decades (Simpson, 1965).

Enzymes, In enzymatic tests, the molecules at the beginning of the process,

called substrates, are converted into different molecules, called products. Almost all

chemical tests in a biological cell need enzymes in order to occur at rates sufficient

for life. Since enzymes are selective for their substrates and speed up only a few tests

from among many possibilities, the set of enzymes made in a cell determines which

metabolic pathways occur in that cell.Like all catalysts, enzymes work by lowering

the activation energy (Ea‡) for a test, thus dramatically increasing the rate of the test.

As a result, products are formed faster and tests reach their equilibrium state more

rapidly. Most enzyme test rates are millions of times faster than those of comparable

un-catalyzed tests. As with all catalysts, enzymes are not consumed by the tests they

catalyze, nor do they alter the equilibrium of these tests. However, enzymes do differ

from most other catalysts in that they are highly specific for their substrates. Enzymes

are known to catalyze about 4,000 biochemical tests. A few RNA molecules called

ribozymes also catalyze tests, with an important example being some parts of the

ribosome. Synthetic molecules called artificial enzymes also display enzyme-like

catalysis. Enzyme activity can be affected by other molecules. Inhibitors are

molecules that decrease enzyme activity; activators are molecules that increase

activity. Many drugs and poisons are enzyme inhibitors. Activity is also affected by

temperature, chemical environment, and the concentration of substrate. Some

enzymes are used commercially (Anonymous a, 2011).

The amount of practicular enzyme present in a cell can be regulated at several

steps in the production of the enzymes and, of course at the stage of enzyme

degradation. In the metabolic control hierarchy, the most complex mechanism for

regulating enzyme concentration involves the processes of gene activation on

repression. In response to specific chemical signals, the transcription of given DNA

sequence into messenger RNA (mRNA) may be initiated or blocked, depending on

whether the signal in questior, is an “inducer” or “repressor” respectively. Gene-level

control can lead to a) increased or decreased quantities of enzymes, b) changes in the

types of enzymes which occur in the cell, c) changes in the relative abundance of

enzyme variants (or isozymes), each of which catalyzes the same given test but, may

display specific catalytic properties (Peter, 1984).

Enzymes being proteins, cannot wishtand the action of strong acid or base.

however, even over pH range in which inactivation does not occur, enzymes exhibit

optima in their activity. In the case of an enzyme which attacks non-ionic subrates,

the optimum pH constant for some particular configuration of electrical charges on

the reactive surfaces of the enzyme protein, in which condition the action on the

subsrate is most efficient. As in the case of the temperature effect, the very existence

of an optimum in the curve suggest the action of two opposing forces. In the case of

the pH effect, it has been suggested that at least two ionizable groups are involved at

the active site. Having different pK`s, an idea which is in agreement with recent

theories concerning the chemical groups at the active site. Ionized subrates will

themselves vary in electrical properties over the pH range, so that enzymes attacking

such substances often show pH optima which differ one subrate to another

(Cantarow, 1962).

According to (Anonymous b (2011), Enzymes work in a similar way (locks

and keys). Enzymes complete very specific jobs and do nothing else. They are very

specific locks and the compounds they work with are the special keys. In the same

way there are door keys, car keys, and bike-lock keys, there are enzymes for neural

cells, intestinal cells, and your saliva. Here's the deal: there are four steps in the

process of an enzyme working.

1. An enzyme and a substrate are in the same area. The substrate is the biological

molecule that the enzyme will attack.

2. The enzyme grabs onto the substrate with a special area called the active site The

active site is a specially shaped area of the enzyme that fits around the substrate.

The active site is the keyhole of the lock.

3. A process called catalysis happens. Catalysis is when the substrate is changed. It

could be broken down or combined with another molecule to make something

new.

4. The enzyme lets go. Big idea. When the enzyme lets go, it returns to normal, ready

to do another test. The substrate is no longer the same. The substrate is now called

the product.

CHAPTER IIIPRACTICUM METHOD

A. Time and Place

Day / Date : Monday/November 22nd 2011

Time : 10.00 A.M until 12.30 P.M

Place : Biology laboratory 3rd flour at FMIPA UNM

B. Tool and Material

1. Tools

a) Test tube

b) Pipette

c) Rack of Test tube

d) Bunsen bunner

e) Baker glass

f) Tripod

2. Materials

a) Sprout extract

b) Amilum solution

c) Fehling a and fehling b solution

d) HCL solution

e) NaOH solution

f) pH meter

g) Aquades

C. Work procedure

1. Prepared ten of test tube, give label for all tubes (A1A2A3, B1B2B3, C1C2C3,

and D) then fill all test tube with amilum solution 1ml.

2. Fill extract 1 ml for test tube A, then checked pH and colour, after that

tube test A1 idled for five minutes, A2 idled for ten minutes, and A3 idled

for fifteen minutes, after that heated for two minutes.

3. Fill extract 1 ml for test tube B, added HCL solution three drops,give

fehilng a and fehling b, then checked pH and colour after that test B1 idled

for five minutes, B2 idled for ten minutes, and B3 idled for fifteen minutes,

after that heated for two minutes.

4. Fill extract 1 ml for test tube C, added NaOH solution three drops, then

checked pH and colour, give fehling a and fehling b, after that test C 1 idled

for five minutes, C2 idled for ten minutes, and C3 idled for fifteen minutes,

after that heated for two minutes.

5. Fill fehling A and B 1 ml for test tub D, and seen colour, after that heated

for two minutes.

6. Heated all test tube after idled five minutes concide, and with solution

after idled ten minutes and fifteen minutes.

7. Compared the result of all tubes and made table of its result.

CHAPTER IVOBSERVATION RESULT

A. Observation Result

Table of the result of practicum:

No Tube pH First colour Last colour

1

A

A1 7 Dark to blue Dark to green

2 A2 7 Dark to blue Dark to green+

3 A3 7 Dark to blue Dark to green++

4

B

B1 1 Light blue Light blue

5 B2 1 Light blue Dark blue+

6 B3 1 Light blue Dark blue++

7

C

C1 11 Dark to blue Green to blue

8 C2 11 Dark to blue Green to yellow

9 C3 11 Dark to blue Yellow to red

10 D D - Blue to red Light purple

The picture of the tubes from our experiment:

1) Tube A After heated

Before heated A1 A2 A3

2) Tube B After heated

Before heated B1 B2 B3

3) Tube C After heated

Before heated C1 C2 C3

4) Tube D (Control)

Before heated After heated

B. Discussion

1) Tube A

Tubes A divided into three tube with contained amilum, they are A1,

A2, A3, added extract and after that we got ph 7,then heated ,tube A1 which

heated during fove minutes until two minutes and was changed colour

from dark blue to dark green. Tube A2 which had heated during ten

minutes and and was changed colour from dark blue to dark green+ and

tube A3 which had heated during fifteen minutes and was changed colour

from dark blue to dark green++. This solution perfect because necessarily

pH which at gets is 7 because get natural characters

2) Tube B

Tubes B divided into three tube with contained HCL, they are B1, B2,

B3 ,added extract and after that we got ph 1, then heated ,tube B 1 which

heated during five minutes until two minutes and was changed colour

from light blue to light blue. Tube B2 which had heated during ten minutes

and and was changed colour from light blue to dark blue+ and tube B3

which had heated during fifteen minutes and was changed colour from

light blue to dark blue++. This solution imperfect because necessarily pH

which at gets is 8 until 14 because that solution gets acid character

3) Tube C

Tubes C divided into three tube with contained NaOH, they are C 1, C2,

C3 ,added extract and after that we got ph 11, then heated ,tube C1 which

heated during five minutes until two minutes and was changed colour

from Dark blue to green blue. Tube B2 which had heated during ten

minutes and and was changed colour from Dark blue to green to yellow

and tube B3 which had heated during fifteen minutes and was changed

colour from dark blue to yellow to red. This solution imperfect because

necessarily pH which at gets is 0 until 6 because that solution gets basic

character

4) Tube D

Tube D we used been control tube, because we just dropped Fehling A

and fehling B into the tube, then heated and was changed colour from

blue to red to purple (control negative)

CHAPTER VCONCLUSION AND SUGGESTION

A. Conclusion

After we done this practicum, we could know the mind of this

experiment, we could know and we could conclude if the experiment of the

influence of pH influenced the activity of enzyme is more big. Enzyme

couldn`t work if small pH, and high pH. Enzyme also couldn’t work if the

hight temperature or the small temperature, with the other word, enzyme

could to study when the pH there on the normal situation and on the normal

temperature, pH of amylase according to Hopkins, Cole, and Green (Miller,

1938) is 4,5-4,7

B. Suggestion

1. Suggestion for laboratory

I hope for next practicum tools and materials that need for practicum must

complete and better in order practicum is success. And Bunsen bunner

better utilizes that easy burning

2. Suggestion for Assistant

I hope assistant could give attention for practican about pH normal for

enzyme activity.

3. Suggestion for the all friends

I hope all practicans could understand, and did not take pipette two-time

with different solution

BIBLIOGRAPHY

Anonymous a, 2011. Enzymes.http://en.wikipedia.org/wiki/Enzymes. Accessed at November 20th 2011.

Anonymous b, 2011. Enzymes www.chem4kids.com/files/bio_enzymes.html. Accessed at November 20th 2011.

Cantarow, Abraham. 1962. Biochemistry. USA: W.B.Saunders company

Simpson, George Gaylord. 1965. Life An Introduction to biology. New York: Harcourt

Peter, Hochacka.1974. Biochemical Adaption. London: Princeton university.

Tim Pengajar, 2011. Penuntun praktikum biologi dasar. Makassar: UNM