Plasma proteins • include proteins of blood plasma and proteins of interstitial fluid
Plasma proteins Vladimíra Kvasnicová
protein
Distribution in body fluids • continual movement from blood vesels to intersticium • transport by pinocytosis and through interendothelial junctions • capillary basal membrane ∼ molecular sieve molecule size dependent passage through
Mr
intravascular
(x 103) albumin
66
(%) 42
transferrin
80
32
haptoglobin 1-1
85
50
IgG
144
44
IgA
160
41
haptoglobin 2-2
160
75
α2-macroglobulin
720
92
IgM
971
77
(accepted from book: Clinical Laboratory Diagnostics / Lothar Thomas)
Proteins of interstitial fluid • subcutaneous: albumin
Plasma proteins • include proteins of blood plasma and proteins of interstitial fluid
• lymph: less proteins than in plasma • almost all are glycoproteins • liquor: 200x less than in plasma • some groups of proteins are classified separatelly (enzymes, proteohormones)
• patological fluids: transsudate exsudate
< 30 g/l > 30 g/l
• „total protein“ ~ more than 300 proteins
Individual proteins of blood plasma • proteins are ampholytes: -COOH
-COO- + H+
-NH2 + H+
-NH3+
they are negatively charged under physiological pH
ANIONS The figure is from http://www.beckmancoulter.com/products/instrument/protein/proteomelab_igy_dcr.asp (Feb 2007)
Common functions of plasma proteins • buffer properties (maintenance of pH) • maintenance of oncotic pressure of blood • some transport proteins have an antioxidant function
Classification of plasma proteins • by electrophoretic mobility prealbumins
albumin alpha, beta and gama-globulins fibrinogen
The figure is from textbook: Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley-Liss, Inc., New York, 1997. ISBN 0-471-15451-2
Principal proteins of each fraction
immunoglobulins: IgG, IgA, IgM
α2-macroglobulin haptoglobin
The figure is from textbook: Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley-Liss, Inc., New York, 1997. ISBN 0-471-15451-2
α1-antitrypsin
transferrin
orosomucoid
C3-complement
• by specific function Position of lipoproteins in electrophoretic patern
transport proteins proteins of immune system system of proteases and antiproteases proteins of hemocoagulation system signal proteins enzymes
The figure is from: Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley-Liss, Inc., New York, 1997. ISBN 0-471-15451-2
• by clinical use cardiomarkers tumormarkers acute phase reactants cellular enzymes
cellular proteins
Factors influencing concentration of proteins total protein: 64 – 83 g/l • velocity of synthesis and degradation • distribution in body fluids • loss into the third place
hormones
• elimination from the body cytokines
• hydration of the body
other important factors: • elevation of concentration before taking blood sample body position (↓ in supine position) tightening of arm
• storage of biological speciment
Consequences of abnormal concentrations • change in sedimentation of erytrocytes • swelling • polyuria • increased sensitivity to infections
