1. Blood: Cells and Plasma Proteins
Beth A. Bouchard
BIOC 212: Biochemistry of Human Disease
Spring 2006

2. I. Major functions of blood and its components:
 transport and distribution of essential nutrients to tissues
 removal of waste products
 defense against internal insult
 repair of damaged tissues
II. Two major components of blood: liquid phase and formed elements

3. Plasma vs. serum
Anticoagulated Clotted

5. Red Blood Cells (Erythrocytes)  1011 produced per day
Lack a nucleus and intracellular organelles
(incapable of protein synthesis and repair)
 Contain specific proteins and ions
 Transport oxygen, and remove CO2 and H+
 Finite life span of days before
being destroyed in the spleen

7. Platelets 2 – 3 um 150-400 x 106/mL blood
Normal subcellular structures except they lack a nucleus
Capable of mitochondrial protein synthesis
Circulate in a non-functional state
Platelet function is dependent upon their activation
 Involved in blood clotting
Contain secretory organelles called alpha-granules, which contain proteins important in blood clotting
Circulate for 10 days before being destroyed
2 – 3 um

10. Plasma proteins Synthesized by liver or produced by plasma (B) cells
Albumin
Transferrin
Ceruloplasmin
Enzymes – coagulation enzymes, complement factors
C-reactive protein – acute phase reactant
Immunoglobulins – humoral immunity
Transport proteins

11. ALBUMIN 66 kDa Accounts for ~50% of the total plasma protein and ~ 50%
of the total liver protein production
 Half-life ~ 20 days
 Highly polar
 At pH 7.4 it is anionic with 20 negative charges per molecule

13. Regulation of colloidal pressure
Gaw: Clinical Biochemistry; Churchill Livingstone (1999), p. 44.

14. Causes of decreased plasma albumin:
Decreased synthesis
A. malnutrtion
B. malabsorption
C. advanced chronic liver disease
II. Abnormal distribution or dilution
A. overhydration
B. increased capillary permeability like in
septicemia
Abnormal excretion or degradation
A. nephrotic syndrome
B. burns
C. hemorrhage
D. certain catabolic states
E. loss of protein from the digestive tract
Rare congenital defects
A. hypoalbuminemia
B. analbuminemia

15. TRANSFERRIN
Transports iron in plasma as ferric ions (Fe3+) – each transferrin molecule binds 2 Fe3+
Protects the body against the toxic effects of free iron
Normally 30% saturated with Fe3+ - increased or decreased saturation is indicative of iron overload or deficiency, respectively
 Decreased in inflammatory states due to excessive degradation of transferrin- Fe3+ complexes

16. CERULOPLASMIN Major copper transport protein
 Regulates oxidation-reduction, transport and utilization of iron
Increased concentrations are found in active liver disease or tissue damage
Decreases are sometimes observed in individuals with Wilson’s disease

17. ENZYMES
 Enzymes of the coagulation and complement cascade have a defined function in blood
 Other enzymes reside elsewhere in the body and appear incidentally in the blood – their measurement is of diagnostic value
Creatine kinase
Alanine
aminotransferase
Acid phosphatase
Amylase

18. C-REACTIVE PROTEIN (CRP)
 Major component of the acute phase response and a marker of bacterial infection
 Mediates the binding of foreign polysaccharides, phospholipids and complex polyanions, as well as the activation of complement
 <1 mg/mL in normal plasma
Slightly elevated levels of CRP are indicative of chronic, low-grade inflammation and have been correlated with an increased risk of cardiovascular disease