Lecture 9 - Part 2

Question 1

What contributes to the decrease in rim rate over time?

Answer 1

1. ( S  P) competes (P  S)
2. [S] ↓
3. Enzyme becomes Unstable
4. P may inhibit Enzyme

Subrstrate and product. Rate of rxn decreases with time and eventuqlly stops

Question 2

What is salts relationship with enzymes?

Answer 2

Required by some “E”

Denatures some “E”

Question 3

What is an oxidoreductase?

Answer 3

Oxidoreductase

Transfers H+ or electrons

Question 4

What is hydrolase?

Answer 4

Uses water to break bond

Question 5

What is a lyase?

Answer 5

Adds or removes groups to / from double bond

Question 6

What is a ligase?

Answer 6

Links two molecules

Question 7

What is an isomerase?

Answer 7

Catalyzes geometric changes

-Glucose isomersae converts glucose to fructose

Question 8

What is alpha amylase?

Answer 8

Enzyme used in foo processing

Breaks α (1-4) Linkages: Starch Hydrolysis

Starch  Maltose + Dextrin
-Breaks it down into these corter chain carbs , still polysaccharides but smaller than starch

Viscosity: Larger molucule the larger the viscosity

Question 9

What is invertase?

Answer 9

Enzymes used in food processing

Invertase (Sucrase)

Sucrose  Glucose + Fructose
-Makes invert sugars

Candy Industry

Question 10

What is beta galactosidase?

Answer 10

Enzyme used in food processing

(Lactase)

Lactose > Galactose + Glucose

Some people can lac this enzyme ini their intestines

Question 11

What is cellulase?

Answer 11

Enzyme used in food processing

Breaks β (1-4) Linkages

Cellulose β-Dextrin, Glucose + Xylose

Humans don’t have this enzyme and why we cant eat grass

Question 12

Where can we use cellulase?

Answer 12

Cellulase (Hydrolyze the cellulose polymer) in juice and wine industry

Break the b1-4 links

This enzyme acts on fruit tissue  Liquefy the tissue More juice could be extracted

Question 13

What is pectinate and pectin esterase?

Answer 13

Found naturally in fruits and vegetables

Used in Fruit/Vegetable juice industry

• Breaks down the cellular structures of fruits and vegetables to allow for maximum extraction of the juice

Hydrolyse pectin bond

Question 14

What is pectinases?

Answer 14

Hydrolyze Polymer Chain which results in:

Cloud Formation in the fruit juice

Then the cloud is Filtered Out

Clarify Fruit Juices (Apple)/Wine

Question 15

What does pectin esterase break off?

Answer 15

Pectin Esterase (breaks off –OCH3 group)

Cloud Formation> Filter Out Cloud > Clear Juice/Wine

Question 16

What is phenolase?

Answer 16

Enzymes used in food processing

Phenolic into O-Quinone (Brown Colour)

Desirable? Tea, Coffee

Undesirable? Fresh Fruits (Apples…)

Question 17

What is glucose oxidase?

Answer 17

β-D-Glucose + 02 > D–Glucono-δ-Lactone + H202

Hydrogen peroxide and add the enzyme so we convert it into water

Question 18

What is a catalase?

Answer 18

H202 > H20 + ½ 02
-Remove 50% of the O2 in the making of fruit juices, and leads to less chane in browning rxns to tak eplace

In Citrus Industry, these enzymes are used to remove 02 from the headspace of fruit juices

Net Result:
Uptake of ½ molecule of 02

Question 19

What does lipase do?

Answer 19

aka esterase

Lipase breaks Tri-A.G. down in a step-wise manner:
TRI -A.G. > DI- A.G. > MONO- A.G. + F.A.
-Breaks ester bonds in a step wise manner (tri to di to mono )

Question 20

What is a proteolytic enzymes?

Answer 20

Require Specific A.A > to break the peptide bond

Trypsin: Hydrolyses next to ARG, LYS

Pepsin: Hydrolyses next to PHE

Question 21

How are enzymes used in making high fructose corn syrup?

Answer 21

Starch—1> Maltose—2> Glucose—3> Fructose

Enzymes:

1. α -Amylase
2. Maltase
3. Glucose Isomerase

Question 22

How do immobilized enzymes work?

Answer 22

Normally:
Add E + Food > Complete Rxn > Heat to inactivate E.
E are never reused

Question 23

What does new technology allow for immobilized enzymes?

Answer 23

New Technology:
E can be physically reclaimed

E bonded with insoluble support matrix

Question 24

What is immobilized in the production of high fructose corn syrup?

Answer 24

Immobilized Glucose Isomerase is used in production of high fructose corn syrup

Question 25

What are the characteristics of high fructose corn syrup?

Answer 25

↑ Sweetness
↓Crystallization
↓ Viscosity

Question 26

Where do natural enzyme inhibitors occur naturally?

Answer 26

Soybeans

8 different “proteinase” inhibitors

Kunitz inhibitor: InhibitsTrypsin

Stable pH 1-12
T <30oC

80-90oC > Denaturation

Question 27

What other vegetable has naturally occurring enzyme inhibitors?

Answer 27

Potatoes

Invertase inhibitor

During growth
[ inhibitor]» [invertase]

During storage
[invertase] ↑ but still
[inhibitor]&raquo_space; [invertase]

During cold storage
[invertase] > [inhibitor]