blood plasma protein

Kursk state medical
university
• Name:Dalhatu
Saidu
• Group:31
• Year:2nd year 4th
semester
Department:biochemistry

CONTENTS:
• 1.CHEMICAL COMPOSITION OF BLOOD
• 2.PROTIENS OF BLOOD PLASMA(METHOD OF
SEPERATION,CLASSIFICATION OF BLOOD PROTIENS).
• 3.ALBUMINS(PROPERTIES AND FUNCTION).
• 4.α-globulins,β-globulins,ϒ-globulins.
• 5.ENZYMES OF BLOOD PLASMA(diagnosis of diseases by
means of enzymes).
• 6.LIPOPROTIENS OF BLOOD PLASMA.
• 7.NITROGEN-CONTAINING COMPOUNDS OF BLOOD PLASMA.
• 8.Non-PROTIEN NITROGEN COMPOUNDS OF BLOOD.
• 9.AZOTEMIA(REASONS FOR
DEVELOPMENT,TYPES,COMPENSATION).

When formed elements are removed from blood, a straw coloured liquid
called blood plasma is left. The table below describes the chemical
composition of blood plasma-
PLASMA
WATER(91.5%)
Liquid portion of blood. Acts as solvent and suspending medium for
components of blood; absorbs, transports and releases heat.
PLASMA
PROTEIN(7.0%)
Exert colloid osmotic pressure , which helps maintain water balance
between blood and tissues and regulates blood volume.
ALBUMIN
Smallest and most numerous blood plasma proteins; produces by
liver. Transports proteins for several steroid hormones and for fatty
acids.
GLOBULINS
Produces by liver and plasma cells, which develop from B lymphocytes.
Antibodies help attack viruses and bacteria. Alpha and beta globulins
transport iron, lipids and fat soluble vitamin.
FIBRINOGEN
Produces by liver. Plays essential role in blood clotting.

OTHER SOLUTES(1.5%)
ELECTROLYTES
Inorganic salts. Positively charges ions(cations) include
Na+
,K+
,Ca+
,Mg2+
;
Negatively charged ions(anions) include Cl-
,HPO4
2-
,SO4
2-
,HCO3
-
.
Help maintain osmotic pressure and plays essential roles in
function of cells.
NUTRIENTS
Products of digestion pass into blood for distribution to all body
cells. Includes amino acids(from proteins), glucose(from
carbohydrates), fatty acids and glycerol(from triglycerides),
vitamins and minerals.
GASES
Oxygen, Carbon dioxide and Nitrogen. More O2 is associated with
hemoglobin inside red blood cells; more CO2 is dissolved in
plasma. N2 is present but has no known functions in the body.
REGULATORY
SUBSTANCES
Enzymes, produces by body cells, catalyze chemical reactions.
Hormones, produced by endocrine glands, regulate metabolism,
growth and development. Vitamins are cofactors for enzymatic
reactions.
WASTE PRODUCTS
Most are breakdown products of protein metabolism and are
carried by blood to organs of excretion. Include urea, uric acid,
creatine, creatinine, bilirubin and ammonia.

 Separation
1. Electrophoresis 2. Ultra-centrifuge
A/G=1.5~2.5

Methodofseparationofbloodplasmaprotein;
• Plasma proteins are separated by using the inherent differences of
each protein. Fractionation involves changing the conditions of the
pooled plasma (e.g., the temperature or the acidity) so that proteins
that are normally dissolved in the plasma fluid become insoluble,
forming large clumps, called precipitate. The insoluble protein can
be collected by centrifugation. One of the very effective ways for
carrying out this process is the addition of alcohol to the plasma
pool while simultaneously cooling the pool. This process is
sometimes called cold alcohol fractionation or ethanol fractionation.
It was described by and bears the eponym of Dr. Edwin J. Cohn. This
procedure is carried out in a series of steps so that a single pool of
plasma yields several different protein products, such as albumin
and immune globulin. Human serum albumin prepared by this
process is used in some vaccines, for treating burn victims, and
other medical applications.

General characteristics of plasma
proteins
1. They are synthesized in liver except
immunoglobulin.
2. Almost all plasma proteins are glycoproteins.
3. Many plasma proteins exhibit polymorphism such
as α1-antitrypsin, transferrin, haptoglobin.
4. Each plasma protein has a characteristic half-life in
the circulation.
5. Acute Phase Proteins, APP

Albumin
Albumin (69 kDa), single polypeptide chain having 585
aa with 17 disulfide bonds, is the most abundant
protein (60%) in the blood plasma. (3.5-5.0 g/dl)
Synthesis of albumin:
– Liver produced about 12g albumin per day which represent 25%
of total hepatic protein synthesis and 50% of secreted protein.
half-life: 20 days
– For this reason, measurement of serum albumin concentration
is used to assays liver function test.

Structure
1. Shape: ellipsoid.
2. Charge: pI=4.0.
3. Domain: three major domains.
Human Serum Albumin

. Transport: It can bind and transport many diverse molecules and serve as low-specificity
transport protein, which include:
• a. Metal ions: such as calcium and copper.
• b. Free fatty acid: albumin binds to free fatty acid released by adipose tissue and
facilitates their transfer to other tissue.
• c. Bilirubin: this protects from the toxic side effects of unconjugated bilirubin.
• d. Bile acid: albumin carries the bile acids that are recycle from the intestine to the
liver in the hepatic portal vein.
• e. Hormones: such as thyroid hormones and the steroid hormones.
• Colloid osmotic pressure, is a form of osmotic pressure exerted by proteins in blood
plasma that usually tends to pull water into the circulatory system.
• Because large plasma proteins cannot easily cross through the capillary walls.
• In conditions where plasma proteins are reduced,
• e.g. from being lost in the urine (proteinuria) or from malnutrition,
• there will be a reduction in osmotic pressure, leading to enhanced fluid retention in
tissue spaces (edema
 Function

Colloid osmotic pressure
Low albumin, causing edema.

Clinical aspects
1. Albumin binds different drugs and
strongly affects the
pharmacokinetics of these drugs.
 For example, sulfonamides can
cause the release of unconjugated
bilirubin from albumin by
competitive binding. If given to
infants, sulfonamides may lead to
kernicterus.
2. In cases of liver disease or starvation,
albumin synthesis decreases.
 This lead to edema.

Clinical aspects
3. Hypoalbuminemia
• lowered plasma albumin
• in malnutrition, nephrotic syndrome and cirrhosis of
liver.
4. Albuminuria
• albumin is excreted into urine
• in nephrotic syndrome and certain inflammatory
conditions of urinary tract.
5. Albumin is therapeutically useful for the
treatment of burns and hemorrhage.

α1–Antitrypsin
/α1–Antiproteinase(α1–ATorAAT)
It (52 kDa) is a glycoprotein with 394 aa.
It is a major constituent of α1 globulin fraction of
plasma protein, normal concentration about 200mg/dl.
It is a serine protease inhibitor and can combines with
trypsin, elastase and other protease and inhibits them.

Clinical significance
1. Emphysema: used to represent the abnormal
distension of lungs.
• About 5% is due to the deficiency of α1–AT.
• This is associated with lung infection and increase
the activity of macrophage to release elastase
that damage lungs tissue.
To methionine sulphoxide and activate alpha att.
 Smoking can cause oxidation of Met358

2. α1 –antitrypsin deficiency liver disease
 due to mutant α1 –antitrypsin
accumulates and aggregates to
form polymers, by unknown
mechanism, cause liver damage
followed by accumulation of
collagen resulting in fibrosis
(cirrhosis).

α2 –Macroglobulin
(α2 –MG)
 It (720 kDa) is a glycoprotein with 4 identical subunits, a major constituent
of α2 fraction.
It is a panprotease inhibitor and can combine and inhibit many protease.
It can bind cytokines such as PDGF and TGFβ and target them to particular cells to
affect on cell growth or function.

Clinical significance
•  2 -MG levels are increased in nephrotic syndrome
• a condition wherein the kidneys start to leak out some
of the smaller blood proteins. Because of its size,  2 -
MG is retained in the bloodstream.
• This increase has little adverse effect on the health,
but is used as a diagnostic clue.
nephrotic syndromenormal

β or Hepatoglobin (Hp)
 It (90 kDa) is a glycoprotein.
 It can bind with the free hemoglobin (extra-
corpuscular Hb) in a tight noncovalent complex Hp-Hb
during hemolysis.
 Hp-Hb(155 kDa) cannot pass through glomeruli of
kidney while free Hb(65kDa) can and Hp prevent the
loss of free Hb into urine.
※Low levels of plasma concentration of Hp can diagnose
hemolytic anemia.
t1/2 of Hp: 5 day, Hp-Hb: 90 min.

※Immunoglobulin(Ig)/anti
body(Ab):
※Glycoprotein molecules that
are produced by plasma cells in
response to an immunogen and
which function as antibodies,
mostly associated with γ
fraction.
※But γ-globulin and Ig are not
synonymous.
※Ig is a functional term
※γ-globulin is physical term.
Amountofprotein Mobility
albumin
globulins
+-

General Functions of Immunoglobulin
1. Antigen(Ag) binding
- Ig binds to a specific antigenic determinant
2. Effector functions
- Complement activation
- Binding to various cells such as phagocytic
cells, lymphocytes, mast cells: antibody-
mediated phagocytosis or antibody-dependent
cell-mediated cytotoxicity (ADCC).

Two Forms of Ig
mIg
1. Membrane Ig, mIg
It confers antigenic specificity on B
cells.
2. Secreted Ig, SIg
It can circulate in the blood and
serve as the effectors of humoral
immunity by searching out and
neutralizing antigens or marking them
for elimination.
SIg

 Basic Structure
1. four chains (H2L2): Y shape
two identical light chains (L):
23 kDa
two identical heavy chains (H):
53-75 kDa
2. Disulfide bonds and such
noncovalent interactions as
salt linkages, hydrogen bonds
and hydrophobic bonds to
form heterodimer (H-L).

1. Variable region (V):
VL&VH
2. Constant region (C):
CL&CH
3. Hinge region: flexibility
Hinge
region
Light Chain:
– VL (110 aa) + CL (110 aa)
Heavy Chain:
– VH (110 aa) + CH1-CH3 (or
CH4) (330-440 aa)

In terms of the differences in amino acid sequence
of constant region of heavy chain,
immunglobulin molecules are divided into 5
classes:
– IgG, IgA, IgM, IgD and IgE
Heavy chain:
– 5 types: γ,α,μ,δ and ε.
Light chains
– 2 types: κand λ.
Immunoglobulin Classes and Subclasses

1. IgG - γ heavy chains
2. IgM - µ heavy chains
pentamer
3. IgA - α heavy chains
dimer
4. IgD - δ heavy chains
5. IgE - ε heavy chains
Immunoglobulin Classes of Mammals
dimer pentamermonomer

IgG
 It is the most abundant class in serum, constitutes
about 80% of the total serum Ig.
 4 subclasses, IgG1, IgG2, IgG3, and IgG4.
 All IgG's are monomers. The subclasses differ in the
number of disulfide bonds and length of the hinge region.
IgG1, IgG2, IgG4 IgG3

 Functions of IgG
1. Major Ig in extravascular spaces.
2. Placental transfer: IgG is the only class of Ig that
crosses the placenta.
3. Complement activation.
4. Binding to cells - Macrophages, monocytes, PMNs (polymorphonuclear
leukocyte), and some lymphocytes have Fc receptors for the Fc region of
IgG.

IgA
• Structure
• Serum - monomer
• Secretions (sIgA)
• Dimer
• J chain
• Secretory component
J ChainSecretory Piece

IgA
• Function
• 2nd highest serum Ig
• Major secretory Ig (Mucosal or Local Immunity)
• Found in the body secretions: tears, breast milk, saliva, mucus of the bronchial,
genitourinary, and digestive tract
• IgA is the most predominant antibody in the colostrum, the initial secretion
from the mother’ breast after a baby is born.
• Does not activate complement (unless aggregated)
• Binds to Fc receptors on some cells

IgM
Structure
The largest Ig
composed of 5 Y-
shaped units held
together by a J
polypeptide chain.
1. Pentamer
2. Extra domain (CH4)
3. J chain

 Functions of IgM
1. 3rd highest serum Ig.
2. IgM cannot traverse blood vessels, hence it is restricted to the blood
stream.
3. 1st Ig produced in a primary response to an antigen and serve as first line
of defense.
4. a good complement activation Ig. Thus, IgM is the most effective in
leading to the lysis of microorganisms.
5. Binds to Fc receptors.

IgD
• Structure
• Monomer
• Tail piece
• Properties
• 4th highest serum
Ig, its role in serum
uncertain.
• B cell surface Ig.
• Does not bind
complement
Tail Piece

IgE
• Structure
• Monomer
• Extra domain (CH4)
• Function
• Least common serum Ig
• Allergic reactions
Binds to basophils and mast
cells (Does not require Ag
binding)
• Parasitic infections
(Helminthes)
• Binds to Fc receptor on
eosinophils
• no complement activation
CH4

Plasma enzymes
Functional Non functional
**For example:-
3-Alanine transminase(ALT) 4-Aspartate transminase(AST)
5-Alkaline phsphatase 6-Acid phosphatase
7-Amylase & Lipase enzymes
Izoenzymes1-Lactate dehydrogenase(LDH)
2-Creatine kinase(CK)

Lactate dehydrogenase(LDH)
Lactic acid Pyruvic acid
NAD NADH+H
*LDH is a tetramer(consists of 4 protomers)
*the promoter's are 2 types:-
1-H(after heart)
2-M(after muscle)
so LDH have 5 isoenzymes:-

LDH 1 – Found in heart and red-blood cells and is 17% – 27% of the normal
serum total
*It is formed of HHHH.It increases in myocardial infarction
LDH 2 – Found in heart and red-blood cells and is 27% – 37% of the normal
serum total.
*It is formed of HHHM.It increases in myocardial infarction
LDH 3 – Found in a variety of organs and is 18% – 25% of the normal serum
total.
*It is formed of HHMM.It increases in leukaemia
LDH 4 – Found in a variety of organs and is 3% – 8% of the normal serum total.
*It is formed of HMMM.It increases in viral hepatitis
LDH 5 – Found in liver and skeletal muscle and is 0% – 5% of the normal serum
total
*It is formed of MMMM.It increases in viral hepatitis

Creatine kinase (CK)
Creatine Ceatine phosphate
ATP ADP
*CK is a dimmer (consists of 2 protomers)
*the protomers are 2 types:
1-B (after brain)
2-M (after muscle)
*so CK has 3 isoenzymes:-

.CPK1 (CPK-BB) is the characteristic isoenzyme in brain and is in
significant amounts in smooth muscle and is 0% of the normal serum
total.
**It increases in brain tumors.
.CPK2 (CPK-MB) accounts for about 35% of the CPK activity in cardiac
muscle , but less than 5% in skeletal muscle and is 0% of the normal
serum total.
**It increases in heart diseases.
.CPK3 (CPK-MM) is the predominant isoenzyme in muscle and is
100% of the normal serum total.
**It increases in skeletal muscle diseases.

Alanine transminase(ALT)
*It is also called serum glutamic pyruvic transminase(SGPT)
*ALT is particularly diagnostic of liver involvement as this
enzyme is found predominantly in hepatocytes.
*It increases in liver & heart diseases.
*It catalyzes transfer of amino group (NH2) from amino
acid (alanine) to a-keto acid producing a new amino acid &
a new keto acid

Glutamic oxalacetic
transminase(SGOT)
Aspartate transminase(AST)
*It is also called aspartate glutamic oxalacetic
transminase(SGOT)
*It increases in liver & heart diseases
*When assaying for both ALT and AST the ratio of the level of these two enzymes can
also be diagnostic. Normally in liver disease or damage that is not of viral origin the
ratio of ALT/AST is less than1.with viral hepatitis the ALT/AST ratio will be greater
than1.
*The level of AST elevation in the serum is directly proportional to the number of cells
involved as well as on the time following injury that the AST assay was performed.
Following injury, levels of AST rise within 8 hours and peak 24–36 hours later. Within
3–7 days the level of AST should return to pre-injury levels unless further injury occurs.
* Although measurement of AST is not, in and of itself, diagnostic for myocardial
infarction, taken together with LDH and CK measurements the level of AST is useful for
timing of the infarct

lipoproteins of blood
• Molecular complexes that consist of lipids and proteins. They
function as transport vehicles for lipids in blood plasma.
• Lipoproteins deliver the lipid components (cholesterol and
triglyceride etc.) to various tissues for utilization.

Classification of plasma lipoproteins
according to their density
• Chylomicron (CM)
• Very low density lipoprotein (VLDL)
• Intermediate density lipoprotein (IDL)
• Low density lipoprotein (LDL)
• High density lipoprotein (HDL)

• Each contains different
kinds and amounts of
lipids and proteins
• The more protein,
the higher the
density
• The more lipid, the
lower the density
• Each has different
function
Lipoproteins

Classification of plasma lipoproteins according to
their electrophoretic mobility
(CM)
a-lipoprotein (HDL)
Pre-b-lipoprotein (VLDL)
b-lipoprotein (LDL)
CM
1967, Fredrickson et al.

What do lipoproteins do?
• Serve to transport lipids and lipid-soluble compounds
between tissues and organs
• Substrates for energy metabolism (TG)
• Essential components for cells (PL, C)
• Precursors for hormones (C)
• Lipid soluble vitamins
• Precursors for bile acids (C)

VLDL
• VLDL are made by liver. Liver synthesizes TG and cholesterol and
packages them into VLDL for export into blood.
• Most lipid in the core of VLDL is triglyceride
• Nascent VLDL contain apoB100. In blood nascent VLDL pick up
apoE and apoCs from HDL and become matured VLDL.

VLDL
• In the capillaries of various tissues, LPL degrades TG to fatty acids
and glycerol, which enter the tissues by diffusion. ApoC-II is needed
in this step to activate LPL.
• When VLDL loses triglyceride, it transforms into VLDL remnant,
also named as IDL (intermediate-density lipoprotein).
• During the process, some apolipoproteins (apo As and apoCs) are
transferred back to HDL.
• VLDL function: Deliver TG from liver to peripheral tissue cells.

Fates of VLDLremnants (IDL)
• Results from loss of TG in VLDL
• Contains relatively more cholesterol esters
• Taken up by liver or transform into LDL
1) A proportion of the VLDL remnant (IDL) is
taken up by liver through the LDL receptor
(apoE-mediated).
2) The other remnant is further acted upon by
hepatic lipase (HL) and converted into LDL.
LDL loses all apolipoproteins except apoB100.
VLDL remnant

LDL
Most core lipid in LDL is cholesterol ester.
ApoB100 is only apolipoprotein in the surface.

Non-Protein
Nitrogen(NPN)
Compounds

Non-protein Nitrogen Compounds
• The determination of nonprotein nitrogenous substances in the
blood has traditionally been used to monitor renal function.
• Nitrogen containing compounds that are not proteins or
polypeptides
• Useful clinical information is obtained from individual
components of NPN fraction

Clinically Significant NPN
• The NPN fraction comprises about 15 compounds
• Majority of these compounds arise from
catabolism of proteins and nucleic acids

Clinical Application
•Measurement of urea is used to:
• evaluate renal function,
• to assess hydration status,
• to determine nitrogen balance,
• to aid in the diagnosis of renal disease,
• and to verify adequacy of dialysis.

Azotemia
Azotemia characterized by abnormally high levels
of nitrogen-containing
compounds, such as urea, creatinine, various body
waste compounds, and other nitrogen-rich compounds in the
blood.
It is largely related to insufficient filtering of blood by the kidneys

Types
1.Prerenal Azotemia
2.Primary Renal Azotemia
3.Postrenal Azotemia

All forms of azotemia
are characterized by
a decrease in the
GFR of the kidneys
and increases in BUN
and serum creatinine
concentrations.
The BUN-to-
creatinine ratio is
a useful measure
in determining
the type of
azotemia.
A normal BUN:Cr
is equal to 15.
GFR
BUN &
Creatinine
15

1. Prerenal azotemia
Prerenal azotemia is caused by a
decrease in blood flow
(hypoperfusion) to the kidneys.
It can occur following hemorrhage,
shock, volume depletion,
congestive heart failure, and
narrowing of the renal artery
among other things.
The
BUN:Cr
in
preren
al
azotem
ia is
greater
than
20.
H
y
p
o
p
e
r
f
u
s
i
o
n

2. Renal azotemia
Renal azotemia (acute renal failure) typically leads to uremia. It is
an intrinsic disease of the kidney, generally the result of renal
parenchymal damage.
Causes: renal failure, glomerulonephritis, acute tubular necrosis, or
any other kind of renal disease.
The BUN:Cr in renal azotemia is less than 15.
In cases of renal disease, glomerular filtration rate
decreases, so nothing gets filtered as well as it normally would.

3. Postrenal azotemia
Blockage of urine flow in an area below the kidneys results in
postrenal azotemia.
Causes: vesicoureteral reflux, blockage of the ureters by
kidney stones, pregnancy, compression of the ureters by cancer,
prostatic hyperplasia, or blockage of the urethra by kidney or
bladder stones.
The BUN:Cr in postrenal azotemia is >15.

Signs and symptoms (prerenal
azotemia)
Oliguria or anuria
Fatigue
Asterixis (flapping tremor)
Decreased alertness
Confusion
Pale skin
Tachycardia

Xerostomia
Thirst
Edema
Orthostatic blood pressure
Uremic frost, a condition that occurs when urea and urea derivatives
are secreted through the skin in sweat, which evaporates away to leave solid
uric compounds, resembling a frost.

Treatment
Dialysis
Medications to increase
cardiac output and increase
blood pressure, and the
treatment of the condition
that caused the azotemia.

blood plasma protein

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