Topic 4: Functions, fractination and changes of Plasma Proteins Flashcards
What should be mentioned in this topic?
- Synthesis
- Functions
- Fractionation
- Pathological Changes
Synthesis:
Almost all the proteins are synthesised in the liver except for gamma globulins, HDL and VLDL and i.c. enzymes
Functions:
- Maintaining oncotic pressure (albumin, keeps water in circulation)
- Transport functions of Albumin
- Transport functions of globulins
- Lipids bind to proteins forming lipoproteins
- Blood sedimentation
- Buffer
- Blood clotting
- Immunity
- Enzymes in the plasma (hormone inactivation, diagnostic importance)
- Protein metabolism (change constantly)
Functions:
Transport functions of Albumin:
- Fatty acids
- Bilirubin
- Hormones
- Vitamins
- Metal ions
Functions:
Transport functions of globulins:
- Transferrin
- Haptoglobin
- Transcortin
- Thyroxin Binding Globulin - Transcobalamin
- Lipoproteins
Functions:
Lipids bind to proteins forming lipoproteins:
- VLDL
- LDL
- IDL
- HDL
Functions:
Blood sedimentation
- Clinical parameter
- In case of infections acute phase proteins appear in the plasma.
- These are produced by the liver
- Bind to the surface of red bloods cells reducing the charge, causing less repulsion
between the red blood cells and thus sedimentation becomes faster.
Functions:
Buffer action:
Plasma proteins are responsible for 7% buffer capacity of blood, 15% buffer capacity of the plasma
Functions:
Blood clotting
- All of the factors involved in blood coagulation except for Ca2+ circulate in the
intravasal compartment as inactive precursors - Also responsible for anticoagulation and fibrinolysis
Functions:
Immunity:
- Immunoglobulins
- Proteins of non-specific immunity
- Signal proteins and peptides
Fractionation:
- Paper electrophoresis
- Gel electrophoresis
- Immunoelectrophoresis
- Ion Exchange chromatography
- HPLC
- Ultracentrifugation
- Gel-filtration
- Affinity Chromatography
Fractionation:
Paper electrophoresis
Only Albumin and Fibrinogen can be separated with this method. The rest of the
proteins can be found in the globulin fraction.
Fractionation:
Gel electrophoresis
Seperated into albumin, and globulins (a1, a2, b, g)
Fractionation:
Immunoelectrophoresis
Antibody distributed in a gel poured on a sheet of glass develops precipitation arcs with the antigen in the electric field
Fractionation:
Ion Exchange chromatography
Separates proteins on the basis of their charge
Fractionation:
HPLC
High Pressure Liquid Chromatography: divides proteins in a solid phase column
under high pressure perfusion
Fractionation:
Ultracentrifugation
Spinning tubes at high G to separate macromolecules according to their sedimentation constants
Fractionation:
Gel-filtration
Smaller molecules have to pass through the polysaccharide beads and hence move
slower than bigger beads which just bypass the beads.
Fractionation:
Affinity Chromatography
One covalently binds a specific antibody formerly produced against the protein to the granules of the solid phase. The proteins will then be selected from the mixture by a special recognizing system.
Pathological Changes
- Hypo and Hyperproteinemia
- Dysproteinemia
- Paraproteinemia
- Defect-proteinemia
Pathological Changes:
Hypo and Hyperproteinemia
Brought about by starving, kidney disease
Pathological Changes:
Dysproteinemia
Ratio changes
Pathological Changes:
Paraproteinemia
Pathological proteins appear
Pathological Changes:
Defect-proteinemia
Lack of some of the fractions
