EXP 8: Enzymes

Enzymes

Complex organic compounds with definite chemical structure, secreted by living cells

Have the property of initiation and hastening chemical reactions without being affected in the process

1. Oxidases

2. Catalases

3. Peroxidase

Types of Enzymes used in the experiment

Oxidases

One of the types of enzymes used in the experiment

Enzymes that catalyze redox reactions; use oxygen as electron acceptor (oxidizing agent)

Catalases

One of the types of enzymes used in the experiment

Enzymes that catalyze the decomposition of hydrogen peroxide (H2O2) to oxygen (O2) and water (H2O)

Peroxidase

One of the types of enzymes used in the experiment

Enzymes that catalyze the oxidation of a hydrogen donor (or electron donor) with the help of peroxides (like hydrogen peroxide (H2O2))

Oxidases

Identify the general name of the enzymes present in apples, guavas, and chicos.

Polyphenol Oxidase (PPO)

What specific enzyme in fruits are responsible for browning of fruits when exposed to atmospheric air?

Tyrosinase

Bifunctional copper-containing oxidase having both catecholase and cresolase activity

Orthohydroxylation

Addition of two -OH groups in ortho-directing substitution

Melanin

What is the final product of oxidation of fruits?

Condensation

What is the process that results in melanin?

Monophenol —PPO+O2→ Ortho-diphenol/Catechol —PPO+O2→ Orthoquinone → Melanins

What is the mechanism of oxidation of fruits? (Include intermediate products)

Potato

What is the main source of catalase?

Hydrogen Peroxide (H2O2)

What acts as the oxidizing and bleaching agent?

Oxidizing & Bleaching Agent

What does Hydrogen Peroxide (H2O2) act as?

False (The Boiled Filtrate exhibited LESS bubble formation since the catalase denatured after being boiled.)

True or False: The Boiled Filtrate in the part Oxidase in Potato exhibited more bubble formation.

Oxygen Gas (O2)

What are the bubbles?

1. Monophenol Oxidase/Tyrosinase

2. Polyphenol Oxidase/Catechol Oxidase

3. Cytochrome Oxidase

3 Oxidases

Monophenol Oxidase/Tyrosinase

One of the types of Oxidases

Responsible for oxidizing phenol → catechol → O-quinone/benzoquinone → Condensation brown compounds of unknown composition

Cresolase Activity

What is the activity of Monophenol Oxidase/Tyrosinase called?

Polyphenol Oxidase/Catechol Oxidase

One of the types of Oxidases

Acts on catechol → o-quinone → unknown brown compounds

Also acts of pyrogallol → purpurogallin

Catecholase Activity

What is the activity of Polyphenol Oxidase/Catechol Oxidase called?

Cytochrome Oxidase

One of the types of Oxidases

Acts in conjunction with cytochrome, oxidizing phenylenediamine + alpha-napthol → indophenol

Bethelot’s Reaction

What is the activity of Cytochrome Oxidase called?

Arene

Another name for an aromatic hydrocarbon

Phenol (C6H5OH)

Identify the arene.

Catechol (C6H4(OH)2)

Identify the arene.

Pyrogallol (C6H3(OH)3)

Identify the arene.

Catalase, Oxidase, Peroxidase

What enzymes are present in the potato?

1. Phenol: Light pink to pink

2. Catechol: Carmine red to red-orange

3. Pyrogallol: Tan to brown

What were the initial color results in the part Oxidase from Potato?

1. Phenol: Light pink

2. Catechol: Light Orange

3. Pyrogallol: Brown

What were the final color results in the part Oxidase from Potato?

True

True or False: Peroxidase is a hemoprotein.

Hydrogen Peroxide (H2O2)

What is added in the part Peroxidase from Potato?

1. Phenol: Flesh-Like

2. Catechol: Deep Red

3. Pyrogallol: Dark Brown

What were the final color results in the part Peroxidase from Potato?

Phenol-Oxidase

What cofactor is required for peroxidase?

Catalase

What enzyme is present in liver?

1. Potato

2. Liver

Identify the sources of Catalase in the experiment.

Hydrogen Peroxide (H2O2)

What was added in the part Catalase from Liver?

Glowing Splint

What is the Test for an Oxidizing Gas?

Liver

Filter of the body that uses enzymes as catalysts and makes harmful substances less toxic

Source of oxygen

What is the purpose of hydrogen peroxidase?