Classification of proteins Flashcards
1
Q
How do we classify proteins ?
A
- Based on structure
- Based on composition
- Based on functions
2
Q
Classification based on structure
A
- Fibrous proteins
- Globular proteins
- Intermediate proteins
3
Q
Classification based on composition
A
- Simple Proteins
- Conjugated proteins
4
Q
Classification based on functions
A
- Structural
- Enzymes
- Hormones
- Respiratory pigments
- Transport proteins
- Contractile proteins
- Storage proteins
- Immunoglobulins
- Toxins
5
Q
Fibrous Proteins
A
- Linear
- Tough & strong
- Long parallel polypeptide chains cross linked at regular intervals
- Perform structural functions in the cells
- Usually do not have a (complex) tertiary structure
- Insoluble in water
- Most important structure: secondary structure
6
Q
Examples of fibrous proteins
A
- Collagen
- Elastin
- Myosin
- Keratin
- Silk
7
Q
Globular proteins
A
- Spherical/globular shape
- Polypeptide chain tightly folded into spherical shapes
- Physically softer
- Most proteins in cells are globular proteins
- Function: form enzymes, antibodies and some hormones
- Readily soluble in water
- Most important structure: Tertiary Structure
8
Q
Examples of globular proteins
A
- insulin
- hemoglobin
- albumin
- DNA polymerase and RNA polymerase
9
Q
Intermediate proteins
A
- Intermediate shape more or less linear
- Soluble in water
10
Q
Example of intermediate protein
A
Blood clotting proteins
11
Q
Simple proteins
A
- Composed of only amino acids, relatively simple structure
12
Q
Examples of simple proteins
A
- Myosin
- Collagen
- Keratin
- Insulin
13
Q
Conjugated proteins
A
- Complex, contains one or more non-amino acid component called prosthetic groups, essential for biological function.
- Usually globular and soluble in water
- Most enzymes are conjugated proteins
- Further classification based on the nature of the prosthetic groups
