Functional Variety of Proteins

Proteins: organic compounds containing carbon (C), hydrogen (H), oxygen (O), nitrogen (N) and

sometimes sulphur (S).

What I need to know:-

1. Proteins are held in 3d shape2. Proteins are held by bonds3. Types of proteins and their functions

Bonds in proteins1. Peptide bonds

Proteins are build up of sub-units called amino acids. These are joined together by chemical links called PEPTIDE BONDS.

GCUCGA A G G

tRNA

GCU

AA1

tRNA

CGA

AA2

The product – POLYPEPTIDE CHAIN (eventually a protein)

The sequence of amino acids determines the protein’s structure and function.

2. Hydrogen bonds

Weak hydrogen bonds form between amino acids in a polypeptide chain causing the chain to coil into a spiral.

3. Other linkages

There are different cross-connections that bridges sulphur atoms with hydrogen bonds. These are

important because they determine the final structure of the protein and so determine the function of the

protein. They lead to the formation of FIBROUS or GLOBULAR proteins.

Types of proteinsA HUUUUGEEE amount of proteins exist in living things

– the human body has 10,000 +.

They are classified as either:FibrousGlobular

Conjugated (Globular + non protein part)

Fibrous proteinsFIBROUS proteins are formed by several spiral-shaped polypeptide molecules link together giving it a rope-like structure.

Example:

Collagen – found in bone providing inelastic, rigid support.

Globular protein

GLOBULAR proteins are formed with polypeptide

chains fold into a spherical shape. This type of protein are vital for all living cells

and perform many functions:

EnzymesStructural proteins

HormonesAntibodies

.

Conjugated proteins

These proteins are globular but also consist of a non-protein chemical.

GLYCOPROTEIN - made up of protein and a carbohydrate. For example, mucus that helps lubricate and protect parts of the body.

Examples:

HAEMOGLOBIN – pigment that transports oxygen in blood. Consists of the protein globin and haem (non-protein containing iron).

Protein function• You will have come across many proteins

before and covered some of the many roles they undertake in living organisms.

• Research one of the proteins listed below and complete its ID

keratin

tubulin

insulin

porin

pepsin

catalase

amylase

haemoglobin

antibody

myosin

actinelastin

phosphorylase

oxytocin

cytochromes

collagen

helicase

integrins polymerase

kinase

Structure:

__(globular/fibrous)__

Location: _____________________________

Function: _____________________________

_____________________________

______________________________

Protein name

Simple diagram of the protein itself or showing what it does.

Glossary

• CONJUGATED PROTEIN – a protein which has a non-protein component associated with it. Examples include glycoproteins, lipoproteins and haemoglobin.

• FIBROUS PROTEIN – a protein which forms fibres and has a structural rather than enzymatic function. Examples include keratin and collagen.

• GLOBULAR PROTEIN – a protein which folds to give a complex 3-D tertiary structure. Examples of these are enzymes, hormones and antibodies.

• PEPTIDE BOND – The C-N bond linking two amino acids together.