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Biochem Ca1 Cram > Plasma > Flashcards

Plasma Flashcards

1
Q

Composition of plasma and forced elements (with specifics) in blood

A

Plasma 55%
Forced elements (blood cells/cell fragments) 45% —> Buffy coat= leukocytes & platelets (less than 1%)
Erythrocytes = (45%)

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2
Q

What is blood serum

A

clear yellowish fluid that remains from blood plasma after clotting factors (such as fibrinogen and prothrombin) have been removed by clot formation.

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3
Q

6 constituents of blood plasma with further examples if possible

A

• Water – 92% by weight
• Plasma Proteins
• Nutrients – sugars, amino acids, lipids, cholesterol, vitamins and trace elements
• Electrolytes
• Dissolved Gasses – including O2 and CO2
• Waste Products

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4
Q

4 types of plasma proteins . With composition. And further examples if needed.

A
  1. Albumin (50-70%)
  2. Globulins (30-50%)
    a-globulins : a1 and a2-globulins
    b-globulins: b1 and b2-globulins
    g-globulins
  3. Fibrinogen (4-5%)
  4. Regulatory proteins (<1%)
    Enzymes, pro-enzymes, hormones
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5
Q

Total conc. Of plasma proteins and individual plasma proteins.

A

§ Total concentration = 65 – 80 g ⁄ l
• Albumin = 35 – 50 g/L
• Globulins = 20 – 35 g/L
• Fibrinogen = 2-4 g/L

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6
Q

Where does biosynthesis of plasma proteins happens

A

biosynthesis:
• liver(mostly)
• lymphocytes(immunoglobulins)
• enterocytes(eg.apoproteinB-48)

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7
Q

Where does degradation of plasma proteins happen.

A

– hepatocytes
– Reticuloendothelial system
(complexes of antigen-antibody, haemoglobin-haptoglobin)

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8
Q

Charge of plasma proteins at physiological pH with example

A

Negative ex. Albumin

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9
Q

What are 4 types of plasma proteins (2 main categories) based on composition with examples

A

Simple proteins
– Albumin
Conjugated proteins
– Glycoproteins
• E.g. Ceruloplasmin, a1-acid glycoprotein,transferrin,
fibrinogen
– Lipoproteins
• E.g. VLDL, IDL, LDL, HDL, Chylomicrons
– Metaloproteins
• ferritin

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10
Q

3 methods of serum protein separation

A

• Electrophoresis
• Salt fractionation
• High-performance liquid chromatography(HPLC)

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11
Q

What is salt fractionation

A

• As the salt concentration is increased, salt ions compete for the water molecules at hydrated groups of proteins, resulting in precipitation of protein out of the solution.
• The larger proteins are usually precipitated first.
• This phenomenon is referred to as “salting out” of protein.
• Ammonium sulphate is commonly used.
• Globulins are the proteins precipitated by half saturation.
• Albumin is precipitated by full saturation.

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12
Q

What is electrophoresis

A

– The movement of charged molecules in an electric
field
– The rate of migration is dependent on the net electrical charge of the molecule, size, and shape of the molecule, buffer pH, properties of the support medium, time frame for the procedure and temperature of the operating system`

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13
Q

2 uses of electrophoresis

A

Hb electrophoresis
serum protein electrophoresis

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14
Q

Describe peaks in electrophoresis of serum protein

A

Albumin largest peak. Then a1, a2, B, Y

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15
Q

2 examples of albumins

A

albumin
pre-albumin (transthyretin)

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16
Q

5 examples of a1 globulins

A

thyroxin-binding globulin
Transcortin
a1-antitrypsin
a1-lipoprotein (HDL)
a1-fetoprotein
a1-acid glycoprotein
Retinol binding protein

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17
Q

4 examples of a2 globulins

A

Haptoglobin
Ceruloplasmin
Plasminogen
a2-macroglobulin

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18
Q

6 examples of B globulins

A

transferrin
hemopexin
b-lipoprotein (LDL)
fibrinogen
C-reactive protein
Beta-2 microglobulin

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19
Q

5 examples of gamma globulins

A

IgG

IgM

IgA

IgD

IgE

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20
Q

4 Function of albumin

A

transport of
free fatty acids,
bilirubin,
calcium,
drugs

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21
Q

Function of transferin

A

Transport iron

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22
Q

Cerulplasmin function

A

Transport of copper

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23
Q

2 function of transcortin

A

Transport of cortisol and corticosteron

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24
Q

Function of lipoprotein

A

Transport lipid

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25
Q

Function of haptoglobin

A

Transport free Haemoglobin

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26
Q

Function of thyroxin binding globulin

A

Transport thyroxin

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27
Q

Function of retinol binding protein

A

Transport of retinol

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28
Q

Function of plasma proteins in osmotic regulation

A

– Plasma proteins are colloidal and non-diffusable and exert
a colloidal osmotic pressure ( a.k.a oncotic pressure which is osmotic pressure caused by plasma proteins )
– Albumin content is most important in regulation of colloidal osmotic or oncotic pressure.

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29
Q

Function of plasma proteins in catalytic function

A

– e.g. lipases for removal of lipids from the blood
– Prothrombin and other proenzymes in clotting cascade
– Ceruloplasmin

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30
Q

Function of plasma proteins in protective function

A

– Immunoglobulins combine with foreign antigens and
remove them.
– Complement system removes cellular antigens.
– Enzyme inhibitors remove enzymes by forming complexes with them. e.g. a1-antitrypsin combines with elastase, trypsin and protects the hydrolytic damage of tissues such as lungs.
– Acute phase proteins. E.g. a1-antitrypsin, a2- macroglobulins, CRP

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31
Q

Function of plasma proteins in blood clotting

A

Involved in clotting mechanism and prevent excessive blood loss
Ex. Clotting factors IX, VIII, thrombin, fibrinogen
Lack of these proteins can cause haemophilia , thrombus formation

32
Q

Functions of plasma proteins on anticoagulant activity/ thrombolysis

A

Plasmin breaks down thrombin and dissolves clot . Protein c & s

33
Q

Function of plasma protein in buffering capacity

A

Help maintain acid - base balance

34
Q

4 General properties of plasma proteins

A

• Synthesized as pre-proteins on membrane-bound polyribosomes; then they are subjected to post- translational modifications in ER and Golgi apparatus
• Almost all of them are glycoproteins
– Exception: albumin
• They have characteristic half-life in the circulation. – (albumin – 20 days)
• Many of them exhibit polymorphism. – (immunoglobulins, transferrin…)

35
Q

What is prealbumin/ transthyretin ( amount in normal plasma, function , half life )

A

• The amount in normal plasma is10-40 mg/dl
• Function:
– Binding and transport of thyroxin
– Transport of retinol in assosciation with retinol binding protein
• A marker of protein synthesis.
• Half-Life;2-4days
• thus transthyretin levels transmit a more timely picture of protein metabolism.

36
Q

What is albumin ( amount in normal plasma, function , half life )

A

§ Concentration in plasma: 3.5 – 5.5 g/dL
§ ~ 60% of the total plasma protein
§ Functions:
• maintenance of plasma oncotic pressure (values lower than 20 g leads to edema)
• protein reserve, the source of amino acids
• transport of:
• steroid hormones, free fatty acids, bilirubin, drugs ( sulfonamides, aspirin), Ca2+,Cu2+
• Halflife–approximately20days

37
Q

What is a1- antitrypsin ( amount in normal plasma, 3 functions , feature, where is it formed )

A

• Main globulin of a1 fraction (90%)
• is synthesized in the liver in hepatocytes and
macrophages
• glycoprotein, highly polymorphous (≈75 forms)
• Function:
– Main plasma inhibitor of serine proteases (trypsin,
elastase…)
– during the acute phase increases Þ inhibition of degradation of connective tissue by elastase
– deficiency Þ Emphysema, cirrhosis

38
Q

What is Alpha-fetoprotein(AFP/α1 Fetoglobulin) and what does elevation indicate

A

• A glycoprotein, is the major protein in the human fetal plasma and amniotic fluid.
• the same function of albumin in adult.
• It is very low amounts in adults.
• After birth its conc. decrease with the increase in albumin.
• AFP levels are elevated in patients with hepatoma, germ cell tumors, and yolk sac tumors.
• AFP is elevated also in developmental birth defects and during pregnancy (peak at 13 weeks of gestation).

39
Q

What is ceruloplasmin

A

• It is an enzyme synthesized in the liver.
• Ceruloplasmin carries 90% of the copper in our plasma.
• The other 10% is carried by albumin.
• Apo-ceruloplasmin (without copper) is unstable.
• Ceruloplasmin exhibits a copper-dependent oxidase activity, which is associated with possible oxidation of Fe2+ (ferrous iron) into Fe3+ (ferric iron), therefore assisting in its transport in the plasma in association with transferrin, which can only carry iron in the ferric state.
• Decreased in Wilsons disease, Menkes disease and copper deficiency.

40
Q

What is Wilson’s disease

A
  1. It is rare inherited disease
  2. Plasma ceruloplasmin is markedly reduced and
    Cu2+ levels increase in brain and liver with resultant neurological changes and liver damage. KF rings
41
Q

What is haptoglobin

A

• It is a glycoprotein, produced by the liver
• They form complexes with hemoglobin.
• Such complexes form as the result of intravascular hemolysis.
• Because of their high molecular weight, the complexes can’t be excreted by the kidney; this prevents the excretion of iron in the urine and at the same time protects the kidney from damage by hemoglobin.
• The haptoglobin-hemoglobin complexes are degraded by reticuloendothleial cells.
• A decrease in haptoglobin can support a diagnosis of hemolytic anemia.
• Acute phase protein; preventing iron-utilizing bacteria from benefiting from hemolysis.

42
Q

What is hemopexin

A

• It binds heme and prevents its urinary excretion, thereby retaining heme iron for further use.
• prevents heme’s pro-oxidant and pro-inflammatory effects and it also promotes its detoxification.
• A decrease in hemopexin level can support a diagnosis of hemolytic anemia.

43
Q

What is transferrin

A

It is the major component of β Globulins.
• The main function is to transport Fe3+ ions to tissues
where it is required like bone marrow.
• Transferrin may also transport Cu & Zn.
• regulates the concentration of free iron in plasma.
• The concentration of transferrin increases during
pregnancy and iron deficiency.
• Free iron is toxic, but binding of Fe3+ to transferrin
reduces iron toxicity.
• Transferrin levels are decreased in:
– liver disease (e.g. cirrhosis)
– Chronic infections

44
Q

What is fibrinogen

A

• Glycoprotein,belongs to b2-globulins.
• component of coagulation cascade –fibrin
precursor
• Acute-phase reactant —> inc. acute inflammation

45
Q

What is B2 microglobulin

A

It is present in very small amount in plasma because of it is low molecular weight.
It is a component of histocompatipility antigen complex.
It is excreted in the urine where it is found normally in a concentration of about 0.1mg/l
elevated in multiple myeloma and lymphoma

46
Q

What is C-reactive protein

A

• Major component of the acute phase response and a marker of bacterial infection
• increases markedly after acute infections.
• The exact function of this protein is unknown,
been suggested that it promotes phagocytosis.
• Slightly elevated levels of CRP indicative of chronic, low-grade inflammation and have been correlated with an increased risk of cardiovascular disease.
• The plasma half-life of CRP is about 19 hours.

47
Q

What is APRs

A

Acute phase reactants (APR) are inflammation markers that exhibit significant changes in serum concentration during inflammation.

48
Q

When do APR conc. Change and what conditions can it cause

A

Levels inc during acute inflammatory response
Conc. Change when infection
Surgery
Injury
Cancer
Cause conditions where. Destruction of cells
Reversible cell damage and subsequent repair
Metabolic activation of certain cells (immune cells)

49
Q

What are the importance of positive acute phase reactants

A

• Components of the immune response
– C-reactive protein,complement components(C3&C4),TNF-a, Il-1, Il-6
• Protection against collateral tissue damage
– Reduce oxidative stress
• haptoglobin
• haemopexin
• ferritin
• Caeruloplasmin
– Inhibitors of proteases
- a1-antitrypsin
- a1-antichymotrypsin

• Transport of waste products produced during inflammation :
– haemopexin
– serum amyloid A (SAA)
• Coagulation factors and proteins involved in tissue regeneration :
– fibrinogen
– prothrombin
– factor VIII
– von Willebrandt factor
– plasminogen

50
Q

What are γ Globulins

A

This fraction of plasma contains the immunoglobulins .
• They are often found during inflammatory illness e.g. rheumatoid arthritis and multiple myloma.

51
Q

What are immunoglobulins

A

• Antibodies produced by B cells in response to antigen stimulation of the organism
• React specifically with antigenic determinants
• Structure:
– consist of a minimum of 4 polypeptide chains - 2 heavy (H) a 2 light (L) linked by disulphide bridges
• lightchainscontainconstant(C) and variable (V) region

52
Q

What are PARAPROTEINS (“M-proteins”)

A

• Greatly increased amounts of some normally undetected serum protein is called paraproteinemia
• A paraprotein is a monoclonal immunoglobulin light chain (Bence Jones protein) present in the blood or urine and arising from a clonal proliferation of mature B-cells
• the abnormally-increased protein is sometimes called an M-protein.
• “M” means both monoclonal and meyeloma ,the usual cause of an M-protein
• Especially if the paraprotein is light chains, it may appear in the urine (“Bence-Jones proteinuria”).
• You can test urine for Bence-Jones protein by yourself, using a test tube and a Bunsen burner.
• Bence-Jones protein precipitates on heating (around 40-60 °C), then re-dissolves just before the urine boils.

53
Q

What is multiple myeloma

A

• A neoplastic (malignant) proliferation of a
single clone (group) of plasma cells in bone marrow.
• Complete or incomplete monoclonal immunoglobulin(s) in serum and/or urine at elevated concentrations
Paraprotein appears as a sharp peak (a “spike”), most often in the gamma region, though it may be anywhere. Such a peak indicates the presence of a monoclonal gammopathy.
A majority of detected monoclonal gammopathies are the result of plasma cell myeloma. These patients typically have depression of other gamma globulins (immuneparesis) and albumin.

54
Q

What are 4 other causes of paraproteinemia

A

Waldenstrom’s macroglobulinemia
heavy chain disease
Chronic Lymphocytic Leukemia
B-cell lymphoma

55
Q

What are 3 functional plasma enzymes and functions

A

1.plasma superoxid dismutase
Reduce oxidative stress
2. lecithin-cholesterol acyltransferase (LCAT)
Bound to LDL or HDL
3.inactive zymogens
coagulation factors and factors of fibrinolysis
complement system components
Angiotensinogen

56
Q

Name for 4 plasma proteins that act as antioxidants

A

• Transferrin
• Ferritin
• Haptoglobin
• Haemopexin

57
Q

Name 4 plasma antioxidant enzymes

A

– Ceruloplasmin
– Superoxide dismutase (SOD) -
– Catalase (CAT)
– Glutathione peroxidase (GPx)

58
Q

What is Felton’s reaction

A

H2O2 +Fe2+ →HO• +OH− +Fe3+
• Fenton’s reaction generates HO• free radicals.
• HO• increases oxidative stress.
• Ceruloplasmin removes Fe 2+
• Glutathione Peroxidase (GPx) and Catalase(CAT) remove H2O2
• and thus prevent the Fenton reaction.

59
Q

Name 3 examples of cofactors for antioxidant enzymes

A

• Zn and Cu for superoxide dismutase
• Selenium for glutathione peroxidase
• Heme for catalase

60
Q

7 functions of zinc ?

A

•cofactor and anti-oxidant enzyme (SOD).
• Zn competes with iron and copper in the cell membrane (Iron and copper ions can catalyze the production of radicals from lipid peroxides).
• Zn metallothioneins are also antioxidants
• Zn inhibits the NADPH-oxidase enzyme.
• Cofactor for RNA polymerase,carbonic anhydrase
• For Zinc finger containing transcription factors
• Zinc-Vitamin A inter-relationship

61
Q

6 non functional plasma enzymes and what causes their inc. level

A

1.Alanine aminotransferase
ALT
liver and biliary tract disease
pancreatic disease
2. Aspartate aminotransferase
AST
liver diseases
myocardial damage
disease of skeletal muscle
3.akcaline phosphatase
ALP
liver and biliary tract disease
bone diseases
4.Creatin kinase
CK
disease of skeletal muscle and myocardium
5.Lactate dehydrogenase
LD1-5
Myocardial disease (LD1, LD2) and muscle disease, hepatopathy
6.g-glutamy ltransferasa
GMT
liver and biliary tract disease and pancreatic disease

62
Q

Describe zinc-vitamin A inter-relationship

A

• Zinc aids in the absorption of vitamin A in the intestine
• Zn is required for synthesis of retinol binding protein.
• Zn is a cofactor for retinol dehydrogenase.
• Vitamin A deficiency may reduce zinc absorption.

63
Q

Name 5 other antioxidants in plasma

A

• Ascorbic acid (Vitamin C)
• Uric acid ( conditional pro-oxidant as well)
• Beta-carotine
• Bilirubin
• Alfa-tocoferol (Vitamin E)

64
Q

What is lipoprotein

A

A molecular complex of neutral lipid core surrounded by a shell of apolipoproteins, cholesterol, and phospholipids

65
Q

What is apolipoprotein

A

protein part of a lipoprotein

66
Q

Describe general structure of lipoprotein

A

general lipoprotein particles range in size from 10 to 1000 nm. —
They are composed of —hydrophobic core; cholesteryl esters, triglycerides, fatty acids and fat-soluble vitamins.
—hydrophilic shell; apolipoproteins, phospholipids and cholesterol.

67
Q

Types of lipoproteins in plasma
(divided into seven classes based on density, lipid composition, and apolipoproteins)

A

• Chylomicrons
• Chylomicron Remnants
• Very Low-Density Lipoproteins(VLDL)
• Intermediate Density Lipoproteins(IDL)
• Low-Density Lipoproteins(LDL)
• High-Density Lipoproteins(HDL)
• Lipoprotein(a)

68
Q

3 types of lipoproteins based on electrophoretic mobility

A

— Alpha lipoprotein:
one with electrophoretic mobility equivalent to that of the α1-globulins, e.g., HDL

— Pre-beta lipoprotein: VLDL

— Beta lipoprotein:
one with electrophoretic mobility equivalent to that of the β-globulins, e.g., LDL

69
Q

Correlation between lipid content and density and size and molecular weight

A

higher the ratio of protein to lipid content the higher the density.
The smaller is size and molecular weight

70
Q

4 major functions of apolipoproteins

A

1) Serving a structural role; structural stability and solubility
2) Acting as ligands for lipoprotein receptors
3) Guiding the formation of lipoproteins
4) Serving as activators or inhibitors of enzymes involved in the metabolism of lipoproteins.

71
Q

Describe apolipoproteins

A

• Located on the surface of the lipoprotein molecules.
• The association of core lipids with the phospholipid and protein coat is non-covalent, occurring primarily through hydrogen bonding and van der Waals forces.
• This binding of lipid to protein is loose enough to allow the ready exchange of lipids among the plasma lipoproteins and between cell membranes and lipoproteins.
• Yet they are strong enough to allow the various classes and subclasses of lipoprotein to be isolated by a variety of analytical techniques.

72
Q

4 functions and significance of lipoproteins

A

• Transport of dietary and synthesized triacylglycerol and cholesterol.
• Absorption & transport of fat-soluble vitamins.
• Activates enzymes (e.g. Apo CII on lipoproteins
activates lipoprotein lipase)
• Abnormal levels (dyslipidemias) lead to complications
(e.g. atherosclerosis)
• Biomarkers for diagnosis and risk stratification .

73
Q

Describe 3 pathways of lipoproteins

A

• The exogenous lipoprotein pathway (CM)
• The endogenous lipoprotein pathway
(VLDL>IDL>LDL)
• The reverse cholesterol transport (HDL)

74
Q

Exogenous lipoprotein pathway

A

• Starts with the synthesis of nascent CM(enterocytes)
• CMs are absorbed into lacteals(lymphatic system)
• Enter blood through the lymphatic duct
• Become mature CM (after receiving apolipoproteins
from HDL)
• Distribute triglycerides to peripheral tissues
• Metabolized by lipoprotein lipase
• Become CM remnant
• CM remnants undergo receptor-mediated endocytosis (RME) at the liver.

75
Q

Exogenous lipoprotein pathway

A

• Start with VLDL synthesis in liver
• Distributed to the peripheral tissues via blood
• Metabolized at the peripheral tissues
• VLDL transforms into IDL (IDLs are intermediates between VLDL and LDL. They are not usually detectable in the blood)
• Part of IDL undergoes hepaticRME.
• Some get converted to LDL.
• LDL delivers cholesterol to peripheral tissues
• LDL undergoes hepatic RME.

76
Q

Describe reverse cholesterol transport

A

• HDL does the reverse (reverse cholesterol transport)
• HDL is mainly secreted by the liver and small intestines. The liver, which secretes ~70–80% of the total HDL in plasma, is the main source of HDL in circulation.

• efflux of cholesterol from peripheral cells to HDL,
• esterification of the cholesterol,
• binding of the cholesteryl ester–rich HDL to
the liver (and steroidogenic cells),
• the selective transfer of the cholesteryl esters
into these cells,
• release of lipid-depleted HDL
• The HDL particle itself is not taken up.

77
Q

Clinical significance of lipoproteins

A

— Low HDL (<35 mg/dL), may be associated with increased risk of coronary atherosclerosis, conversely high levels of HDL (>55 mg/dL) appear to have a protective affect.
— High LDL levels have been shown to correlate with coronary atherosclerosis.

Biochem Ca1 Cram (13 decks)

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