Plasma protein

PLASMA PROTEINS

Def.

TypesAlbumin

Ig

FibrinogensFunctions

Immunoglobulins.Def

Type

s

IgG

IgE

IgAIgM

IgD

Contents:

Plasma proteins:

•Are proteins found in the blood plasma, the clear, protein-rich fluid which is left behind when platelets, red blood cells, and white blood cells are removed from the blood.

•Their total concentration is 6-8 g/dl .

Types of plasma proteins: Blood protein Normal

level  % Function

Albumins 3.5-5.0 g/dl 60%

create oncotic pressure and transports other molecules

immunoglobulins 1.0-1.5 g/dl 18% in immune system

Fibrinogens 0.2-0.45 g/dl 4% blood coagulation

alpha 1-antitrypsin

neutralize trypsin that has leaked from the digestive system

Regulatory proteins <1% Regulation of few gene expression

Functions of plasma proteins:The plasma proteins are mostly synthesized in the hepatocytes, except for the immunoglobulins (gamma)which are synthesized in the lymphoreticular system .

The principle functions of the plasma proteins are :

(1) -Maintenance of colloidal oncotic pressure, a function mainly of albumin.

(2- )Transporter or binding proteins e.g:. –Essential metabolites: e.g. lipids (as

lipoproteins) .–Hormones: e.g. thyroxin (thyroid binding

globulin) cortisol (transcortin) .–Metals. e.g. transferrin (transport iron)

and ceruloplasmin (contains Cu2+) .–Excretory products: e.g. bilirubin (bound

to albumin) .–Drugs and various toxic ingested

substances.

(3 -)Defense reactions ,functions which depend on :

a)Immunoglobulins b)The complement system .

(4 -)Coagulation ,When fibrinogen converted to fibrin by founding of coagulation factors such as ( thrombin )

IMMUNOGLOBULINS

Immunoglobulins(Ig) are glycoprotein molecules that are produced by plasma cells in response to an immunogen and which function as antibodies .

Types of Immunoglobulins:There are different types of immunoglobulins: IgG, IgM, IgA, IgD and IgE. All of them have in common that their basic unit is formed by two pairs of peptide chains: a pair of Light chains or L chains (approximately 220 amino acids each) and a pair of Heavy chains or H chains (around 440 amino acids each).

 These four chains in the basic structure are linked through disulfide bridges between cystein residues in the backbone of the peptide chains. Each Light chain is linked to one Heavy chain and each Heavy chain is associated to a Light chain and to the other Heavy chain.

1 )IgG A- It is the immunoglobulin which binds to bacteria and some multicellular organisms ,

B- This make it possible for to be recognized and damaged or ingested by neutrophils and macrophages (phagocytic cells) .

2 )IgE is the immunoglobulin which binds to histamine-containig mast cells and basophils and mediates the release of histamine in .immune reactions

3 -IgA fulfills similar functions to IgG except that it is also found in secretions on body surfaces, such as the respiratory tract mucosa, as well as in plasma .

4 -IgM is synthesized first when any antibody response is mounted. Thus the first antigen-specific immunoglobulin is IgM which is later replaced by IgG .

5 -The function of IgD is not well known .

References:Textbookhttp://www.antibodypedia.comhttp://biochemistryquestions.wordpress.comhttp://en.wikipedia.orghttp://www.youtube.com

PLASMA PROTEINS

Presented by: -Abdel-Aziz Muostafa Mohamed

-Essam Mohamed Naged -Ali Mohamed Ahmed

-Ali Mohamed Ali -Omar El_sayed Ahmed

Thank you