Serum proteins

Normal values

Total serum protein • Total protein: 5.5–9.0 grams per deciliter (g/dL) • :3.5–5.5 g/dL • :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; 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 are a family of globular proteins that have higher molecular weights and water solubility than the . • 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 • β-Globulin • γ-Globulin (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. • . In addition to carrying substances through the bloodstream, beta globulin proteins help fight infection. • . 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.