Serum proteins

Normal values

Total serum protein

• Total protein: 5.5–9.0 grams per deciliter

(g/dL)

• Albumin:3.5–5.5 g/dL

• Globulin:2.0–3.5 g/dL

• Albumin/globulin ratio:

Greater than 1.0

ALBUMIN

• Is the most abundant protein produced in the liver

• Constitutes about half of the blood serum protein it is soluble and

monomeric

• Transports hormone , fatty acid

• It has half life of approximately 20 day

• The gene for albumin is located on chromosome 4

And mutation in this gene result in anomalous protein

• A low molecular weight protein (M.Wt= 65,000 Dalton)

• It prevent leaking the blood from the capillary

Function

• Maintains oncotic pressure

• Transports thyroid hormones

• Transports other hormones, in particular, that are fat-

soluble

• Transports fatty acids ("free" fatty acids) to the liver and

to myocytes for utilization of energy

• Transports unconjugated bilirubin

• Transports many drugs; serum albumin levels can affect

the half-life of drugs

• Competitively binds calcium ions (Ca2+

)

• Buffers pH

• Prevents photodegradation of folic acid

Pathology

Low blood albumin levels (hypoalbuminemia) can

be caused by:

• Liver disease; cirrhosis of the liver is most common

• Excess excretion by the kidneys (as in nephrotic syndrome)

• Burns (plasma loss in the absence of skin barrier)

• Redistribution (hemodilution [as in pregnancy], increased

vascular permeability or decreased lymphatic clearance)

• Acute disease states (referred to as a negative acute-phase

protein)

• Mutation causing an albuminemia (very rare)

• Hyperalbuminemia

1. this condition is a sign of severe or chronic

dehydration.

2. It is possible that a retinol (vitamin A) deficiency

alone could cause albumin levels to become raised.

Patients recovering from chronic dehydration may

develop dry eyes as the body uses up its vitamin A

store. It is interesting to note that retinol causes

cells to swell with water (this is likely one reason

that too much vitamin A is toxic)

3. Hyperalbuminemia is also associated with high

protein diets

How we do albumin analysis?

• Add 1 ml of albumin to Bromcresol (green) in the acidic

medium the green color transforms to a greenish to blue

color and the intensity of the color associated with

albumin concentration and that is measured by

spectrophotometric

Factors that affect analysis ?

• The result is higher if we draw the blood from the patient

standing or after exercise

• In case of urinary infections and during the menstrual

cycle

• After dialysis sessions

Globulin

• The globulins are a family of globular proteins that have

higher molecular weights and water solubility than

the albumins.

• Globulin is made up of different proteins called alpha,

beta, and gamma types.

• Some globulins are made by the liver, while others are

made by the immune system.

• Certain globulins bind with hemoglobin and their

globulins transport metals, such as iron, in the blood and

help fight infection.

• Serum globulin can be separated into several subgroups

by serum protein electrophoresis.

Globulin Can be separated into different fractions on the

basis of their electrophoretic mobility and

sedimentation coefficient:

• α1-Globulin α1-Fetoprotein

α1-Antitrypsin

• α2-Globulin α2-Fetoprotein

Haptoglobin

• β-Globulin Transferrin

Ceruloplasmin

• γ-Globulin Antibodies (immunoglobulins)

which include (Iga ,Igg ,Igm ,Ige)

• Alpha-1 globulin. The protein portion of high-density

lipoprotein (HDL), the “good” type of cholesterol, is

included in this fraction.

• Alpha-2 globulin. A protein called haptoglobin, that binds

with hemoglobin, is included in the alpha-2 globulin

fraction.

• Beta globulin. In addition to carrying substances through

the bloodstream, beta globulin proteins help fight

infection.

• Gamma globulin. This proteins is important in preventing

and fighting infection

Some gamma globulins bind to foreign substances (such

as virus or bacteria) and destroying them by the immune

system

High Globulin Levels caused by:

1. Chronic inflammatory diseases (ex: TB, Syphilis)

2. Bone marrow disorders like multiple myeloma

3. Leukemias

4. Autoimmunity (Systemic lupus, collagen diseases)

5. Rheumatoid arthritis

6. Liver disease (biliary cirrhosis, obstructive jaundice)

7. Carcinoid syndrome

8. Ulcerative colitis

9. Kidney disease (Nephrosis)

10.Chronic infections (parasites, some cases of viral and bacterial

infection like viral hepatitis or HIV)

Low Globulin Levels caused by:

1) Hepatic dysfunction

2) Celiac disease

3) Proteins are not digested or absorbed properly

4) Inflammatory bowel disease (IBD)

5) Acute hemolytic anemia

6) Hypogammaglobulinemia/Agammaglobulinemia

7) Renal disease (A condition in which the kidneys do not filter the

protein from the blood and it leaks into the urine).

MEASUREMENT OF PROTEIN

FRACTIONS

• The protein fraction in plasma can be separated and estimated

using the following methods:

• –Zone electrophoresis

• –Immunochemical methods

• –Chemical methods

• –Ultracentrifugation

Ultracentrifugation

Physical Techniques

• 1.Ultracentrifugation (analytical or Sedimentation

velocity ultracentrifuge) at 60,000 round per.min.

• The boundary between the solvent and the protein is

visualized by an optical system –called (Sehlieren

System).

Advantage

• Most useful for the determination of the mol. wt of

proteins

Disadvantage

• High cost of each analysis and poor resolving capacity

(when applied to whole serum or plasma)

Serum protein electrophoresis

• This test measures specific proteins in the blood to help

diagnose some diseases.

• Proteins carry a positive or a negative electrical charge,

and they move in fluid when placed in an electrical field.

• Serum protein electrophoresis uses an electrical field to

separate the proteins in the blood serum into groups of

similar size, shape, and charge.

How to Prepare for the Test

• The patient may be asked not to eat or drink for 4 hours

before a serum protein electrophoresis test.

• stop taking drugs that could affect the test. Do not stop

taking any medications without first talking health care

provider.

• Drugs that can affect the measurement of total proteins

include chlorpromazine, corticosteroids, isoniazid,

neomycin, phenacemide, salicylates, sulfonamides, and

tolbutamide.

How does it work?

• Blood must first be collected, usually into an airtight vial

or syringe.

• Electrophoresis is a laboratory technique where the

blood serum is placed on special paper

• The paper is exposed to an electric current to separate

the serum protein components into five classifications by

size and electrical charge, those being serum albumin,

alpha-1-globulins, alpha-2-globulins, beta globulins, and

gamma globulins.