BIOCHEM - Enzyme 2

Question 1

classes of enzymes:

Answer 1

Hydrolase
Isomerase
Ligase or Polymerase
Lyase
Oxidoreductase
Transferase

Question 2

TRC: Hydrolysis (Catabolic)

Answer 2

Hydrolase

Question 3

example of Hydrolase

Answer 3

Lipase - breaks down lipid molecules

Question 4

TRC: rearrangement of atoms within a molecule (neither catabolic or anabolic)

Answer 4

Isomerase

Question 5

example of Isomerase

Answer 5

Phosphoglucoisomerase - converts glucose 6 phosphate into fructose 6-phosphate during glycolysis

Question 6

TRC: joining 2 or more molecule together (anabolic)

Answer 6

Ligase or polymerase

Question 7

example of Ligase or polymerase:

Answer 7

Acetyl-CoA synthase - combines acetate and coenzyme A to form acetyl-CoA for the Krebs cycle

Question 8

TRC: splitting a chemical into smaller part without using water (catabolic)

Answer 8

Lyase

Question 9

example of Lyase:

Answer 9

Fructose 1, 6-bisphosphate aldolase - splits fructose 1,6-bisphosphate into G3P and DHAP

Question 10

TRC: transfer of electrons or hydrogen atoms from one molecule to another

Answer 10

Oxidoreductase

Question 11

example of oxidoreductase:

Answer 11

Lactic acid dehydrogenase - oxidizes lactic acid to form pyruvic acid during fermentation

Question 12

TRC: Moving a functional group from one molecule to another (may be anabolic)

Answer 12

Transferase

Question 13

example of transferase

Answer 13

Hexokinase - transfer phosphate from ATP to glucose in the first step of glycolysis

Question 14

As the name implies, they catalyze redox reaction – transfer of electrons.

One molecule would lose an electron and another molecule would eventually gain an electron

Answer 14

Oxidoreductase

Question 15

In organic chemistry, these are also
dehydrogenation reaction

Answer 15

Oxidoreductase

Question 16

there is a subclass of oxidoreductase that is called ____________

malic dehydrogenase,
pyruvate dehydrogenase,
succinate dehydrogenase and
alcohol dehydrogenase

Answer 16

dehydrogenases

Question 17

When we are talking about oxidoreductase, the usual coenzymes are

Answer 17

NAD
FAD or
NADP

Question 18

Whenever we see an enzyme that bears the name dehydrogenase, try to look for the coenzyme right away.

There should be ______________ in that particular reaction.

Answer 18

NAD, FAD or NADP

Question 19

These enzymes catalyze the transfer of functional groups such as methyl,
acetate and phosphate among other things.

Answer 19

Transferases

Question 20

There is a special class of transferases that are called ____________.

They transfer phosphate usually coming from ATP.

Answer 20

kinases

Question 21

One example of transferases is __________.

One of the very first reactions that ______
undergoes when it enters the cell is that it will be phosphorylated at C6.

Phosphate will be attached C6

Answer 21

glucose

Question 22

Phosphate was transferred from ATP to glucose. From ATP it became ADP.

The enzyme is called ___________.

Answer 22

hexokinase

Question 23

They catalyze hydrolytic reactions, adding water across C-C bonds.

These enzymes break bonds by adding water molecule

Answer 23

Hydrolyases

Question 24

Very similar to the enzyme hydrolases

They also break C-C bonds, C-O bonds, C-N bonds and other bonds.

Sometime they generate a ring or a
double bond.

They break bonds but do not incorporate
any water molecules.

Answer 24

Lyases

Question 25

This reaction is catalyzed by __________ The bond between the 2 Cs has been cleaved, making the carboxyl group in the form of CO2. There is no water molecule involved making _________ a form of lyase

Answer 25

pyruvate decarboxylase

Question 26

cleave C-C, C-O, C-N, etc generate C=C bond or ring

Answer 26

Lyase - Pyruvate decarboxylase

Question 27

Also called mutases. They catalyze interconversion between isomers.

Answer 27

Isomerases

Question 28

are molecules that have the same structure but different configuration. Example: fumarate and maleate

Answer 28

Isomers

Question 29

In naming the product, they both can be ___________. One of them can be the product and the other the substrate or vice versa

Answer 29

interconverted

Question 30

(mutases) catalyze isomerization ex: Maleate isomerase

Answer 30

Isomerases

Question 31

They catalyze condensation between 2 substrate with splitting of ATP They form bonds between 2 molecules and there has to be source of energy, and the usual source of energy is ATP

Answer 31

Ligases

Question 32

example of ligases

Answer 32

pyruvate carboxylase

Question 33

__________ is formed by condensation of bicarbonate and pyruvate. A bond here has been formed and the source of energy is the splitting of ATP to ADP in Pi (inorganic phosphate)

Answer 33

oxaloacetate

Question 34

"to tie together"

Answer 34

ligate

Question 35

opposite of lyase

Answer 35

ligases

Question 36

HOW ARE ENZYMES CONTROLLED/REGULATED?

Answer 36

1. Anchoring enzymes in membranes 2. Inactive precursors 3. Allosteric regulation 4. Covalent modification 5. Regulation of enzyme synthesis

Question 37

The cell membrane is composed of 2 layers of phospholipid and inserted into them are integral proteins. Some of these integral proteins are actually ________________.

Answer 37

enzymes

Question 38

When enzymes are inserted into membranes, it allows them to interact efficiently with their substrate. They are locked into that particular area; having nowhere else to go therefore they can act efficiently with their _________.

Answer 38

substrate

Question 39

Proteolytic enzymes are stored as ____________, - Once they have been secreted, they are usually cleaved to yield the active enzyme

Answer 39

zymogens

Question 40

example of Inactive precursors. This is stored in the pancreas. Just before it is secreted, it is cleaved between arginine 15 (Arg 15) and isoleucine 16 (Ile 16) to yield active chymotrypsin.

Answer 40

Chymotrypsinogen

Question 41

In this example, we can see a pathway. The initial substrate A becomes B then becomes C and so on. The final product is E. Each step is catalyzed by a respective enzyme like A becomes B catalyzed by enzyme a.

Answer 41

Allosteric regulation

Question 42

If there is excessive amount of the final product E, it can provide feedback inhibition to the initial enzyme a to slow down the reaction.

Answer 42

Feedback inhibition

Question 43

regulation are inhibitory in nature. Sometimes they can activate an enzyme. This time, it is no longer called an allosteric inhibitor but a ______________.

Answer 43

positive modulator

Question 44

One of the functional groups in the enzyme will be attached to another functional group. In this case, phosphate was attached to serine, rendering the enzyme active. This form of covalent modification is what is known as _____________. The source of phosphate is usually ATP.

Answer 44

phosphorylation

Question 45

The most sophisticated way of controlling enzymes. - Genes are DNA which encode for proteins. Proteins are made through a process of transcription and translation of a particular gene. So gene encodes proteins and enzymes are PROTEINS

Answer 45

Regulation of enzyme synthesis