BIOC- Plasma Proteins

Albumin

– 50–70% of the total plasma proteins
– Serum concentration 3.5 and 5.5 g% in adults
– Synthesized in the liver

Analbuminemia

a lack of serum albumin, results in the absence of transport functions &
osmotic activity, presenting as a benign condition
– The frequency of analbuminemia is less than one per million individuals

Congenital analbuminemia (CAA)

– Mutations in the ALB gene lead to the absence or very low levels of HSA and edema
– Clinical signs include mild symptoms such as fatigue, low blood pressure, and edema
– Patients may exhibit lipodystrophy, high cholesterol contributing to atherosclerosis and
heart problems
– Rarely, hypercoagulability, osteoporosis, and susceptibility to respiratory tract infections

compensatory mechanisms

• Increased Levels of Other Plasma Proteins – The body compensates by increasing the synthesis of other proteins, such as globulins, apolipoproteins, and fibrinogen, which help maintain oncotic pressure.

• Enhanced Capillary Permeability Regulation – Adaptive changes in capillary dynamics may reduce excessive fluid leakage into the interstitial space.

• Increased Lipoproteins – There is often an increase in circulating lipoproteins, which contribute to oncotic pressure and reduce fluid extravasation.

Individuals suffering with analbuminemia have only moderate edema, Why?

α1 - acid glycoprotein (AGP) OR orosomucoid protein (ORM)

– Is highly glycosylated acute phase protein (APP) found in plasma
– APPs exhibit variable plasma levels in response to inflammation

Alpha-1 antitrypsin or α1-Antiproteinase (AAP)

Protects tissues from lytic activity of elastase enzyme
• It is secreted by neutrophils, and
• Degrades elastin protein in lung and liver tissues

Alpha1-Antiproteinase (AAP), also known as α1-antitrypsin

the main serine protease inhibitor of human plasma

α-1 antitrypsin and
makes it inactive

Smoking oxidizes methionine 358 in

Enzyme Elastase

disrupts lung tissues in the absence of α-
1 antitrypsin

liver cirrhosis

Deficiency of alpha-1 antitrypsin leads to juvenile

chronic obstructive pulmonary disease and liver cirrhosis

Persons with ZZ genotype have higher susceptibility to

α2-Globulins: Ceruloplasmin

A major copper carrying protein in the blood

It is an important ferroxidase enzyme, converts ferrous ion
into ferric ion

hemoglobin (Hb)

In healthy individuals, about 10% of red blood cells undergo
hemolysis, releasing

glomerular filtration, preventing free Hb loss in urine

Hg binds with free Hb α-chains, forming a complex that cannot
cross

decreases in this condition

Haptoglobin (Hg) is Useful in diagnosing hemolytic anemia, as its serum concentration

Hemopexin

Exhibits a strong 1:1 affinity for heme

Levels decrease in hemolytic anemia, making it a diagnostic marker for
assessing hemoglobin levels and red blood cell (RBC) count

hemoglobin

Hemopexin binds Heme
while Haptoglobin binds

α₁-antitrypsin (AAT)

Oxidation of methionine-358 destroys the protease-
binding capacity of which plasma protein?

free hemoglobin (Hb)

The clinical significance of plasma protein, haptoglobin,
in reducing oxidative stress is related to its binding to which
molecule?

hemopexin

Which plasma protein has highest binding affinity for
free heme?

Atransferrinemia

– A rare genetic disorder causing the absence of transferrin
– Leads to anemia and hemosiderosis in the heart and liver, ultimately resulting in
heart failure

Retinol binding protein (RBP)

Crucial for embryonic development
• An imbalance in retinol or retinoic acid can lead to early embryo mortality or
developmental malformations

Successful pregnancy requires the precise regulation of retinol
transport and metabolism, orchestrated by RBP

Pregnancy regulation via RBP:

Bence-Jones Protein

– Detected in the blood and urine of multiple myeloma patients, a plasma cell tumor
– A diagnostic threshold for multiple myeloma is more than 3 mg/100 ml, while a
healthy person typically has a value around zero

RBP

Which of the plasma protein plays a critical role in a
successful pregnancy?

Bence-Jones Protein

A patient diagnosed with multiple myeloma may show
which of the protein in his blood and urine samples?

fibrinogen (factor I)

A patient suffering from liver disease has a low serum
concentration of a plasma protein leading to higher bleeding.
Which is that plasma protein?

albumin

In healthy people, which plasma glycoproteins transport
both hydrophobic as well as ionic molecules from blood to
tissues?

Haptoglobin

protects against oxidative stress by binding to free hemoglobin

Hemopexin

binds to free heme in 1:1

Hemolytic anemia

Patient with genetic deficiency of haptoglobin may suffer with

Fibrinogen

is necessary for blood clotting, results in bleeding, concentration is decreased in liver
diseases

blood to the tissues

Albumin a glycoprotein, transports both hydrophobic as well as ionic molecules from the

copper carrying protein in the blood

Ceruloplasmin is a major

Bence-Jones Protein

Diagnostic of multiple myeloma:

Retinol Binding Protein

plays a critical role in a successful pregnancy

lytic activity of elastase enzyme

Alpha-1 Antitrypsin plasma protein protects tissues from