PROTEINS
‫السالم عليكم ورحمة هللا وبركاته‬
OBJECTIVES
• Master how to determine the conc. of protein
in serum/plasma.
• Important of protein estimation in health and
various diseases.
• Understand the principles behind protein
estimation.
Introduction
Proteins are polymers of amino acids linked covalently
through peptide bonds.
Proteins are large molecules and can be split into smaller units
by hydrolysis-amino acids.
Proteins: Classification
Depending upon their solubility and physical properties ,
proteins are divided into three classes.
1- Simple proteins: Simple proteins are those which
contain only amino acids. e.g. albumin and globulin
2- Conjugated proteins: Conjugated proteins are
those which contain a non amino acid component in
addition to the amino acids.
e.g. lipoprotein , phosphoproteins etc.
3- Derived proteins: Derived from simple proteins
(denaturation) e.g. peptones.
Element Components of Proteins
• Major
elements
C, H, O, N, S.
• Trace
elements
P, Fe, Cu, Zn, I, …
Properties of Proteins
• Molecular weights range from 10000-several hundred
thousand
•Generally proteins are soluble in water, except the
membrane proteins which are hydrophobic
•Absorption maxima in the ultraviolet region
•Proteins are charged molecules, but the charge
depend on the pH of the buffer.
•Move under an electric field and can be separated by
electrophoresis
Functions of Proteins
1. Proteins build new tissues of the body.
2. They maintain and replace damaged tissues.
3. They carry out regulating activities as
enzymes and hormones.
4. They are protective as antibodies.
5. They help in other activities such as
movement of skeletal muscles, transport of
oxygen, pigmentation of skin etc.
QUALITATIVE TESTS
XANTHOPROTEIC TEST
MILLONS TEST
NINHYDRIN TEST
METHODS OF PROTEIN
ESTIMATION
 Biuret method
 Bradford method
 Folin- Lowry method
 Kjeldahl method
 Bicinchoninic method
 UV method
 Flourimetric method