Chem Practicum B

Question 1

Functions of proteins in normal physiology?

Answer 1

1Nutrition
2Maintenance of oncotic pressure
3Transport- lipids, bilirubin, calcium, iron, some hormones, some drugs, chylomicrons
4Catalytic function- enzymes
5Immunity: Specific-Immunoglobulin
6Non-Specific-Complement, Cytokines, Interferon, CRP, alpha trypsin
7Some hormones
8Coagulation Factors
9Buffering

Question 2

Def. Salt fractionation

Answer 2

process of purification of protein using salt. The protein competes with
the salt to bind with the water molecules. As the concentration of the salt increases, the solubility of the protein decreases and the protein is precipitated out. Different proteins have different group on their surface and thus different solubility. So they precipitate out at different concentrations of salt. Highly water soluble salt is used. Ammonium sulfate is the most commonly used salt.

Question 3

Zwitterions

Answer 3

dipole ion containing both positive and negative charged groups. Thus they have both acidic and basic group in their surface. This makes them highly soluble in water and less soluble in organic solvent. Amino acids are the example of zwitterions due to the presence of positively
charged amino group and negatively charged carboxyl group on same molecule.

Question 4

Zeta Potential

Answer 4

It is the potential produced by the effective charge on a surface of macromolecule (colloids), usually taken at the boundary between what is moving with the macromolecule and the
rest of the solution.

Question 5

Polysaccharide

Answer 5

long chain of repeating units of carbohydrates joined together by glycosidic bond. The repeating units may be monosaccharide or disaccharide and can be branched.

Question 6

Oligoclonal banding

Answer 6

When various proteins share the same electrophoretic mobility, they are
called oligoclonal bands. For example, immunoglobulins from cerebrospinal fluid appear in a
same γ-range in an agarose gel.

Question 7

Describe the Kjeldahl techniques for determining protein and nonprotein nitrogen

Answer 7

oldest approach for quantifying total serum proteins. This method has good accuracy and precision but is very time consuming and tedious. In this method nitrogen containing compounds are oxidized to NH4+, then in alkaline conditions NH4+ Is converted to NH3. Then NH3
is titrated with HCL.

Question 8

Reasons for hypoalbuminemia?

Answer 8

1.Low production:
-Malnutrition (low AA)
-Liver disease
2.Loss or use after synthesis:
-GI leakage from inflammation and disease of GI mucosa
-Renal disease (glomerulonephritis, nephrotic syndrome)
-Burns
-Inflammation
-Neoplasm
-Pregnancy
3.Edema → loss of intravascular oncotic pressure
-Ascites

Question 9

Reasons for hyperalbuminemia?

Answer 9

1. Dehydration - Hemoconcentration
   2 .Due to other pathologies (Three Cs):
   -Cancer
   -Chronic infection (high protein synthesis)
   -CHF (low GFR so more protein retention)

Question 10

Globulin levels may be elevated in what conditions?

Answer 10

Chronic infections (parasites, some cases of viral and bacterial infection)
Liver disease (biliary cirrhosis, obstructive jaundice)
Carcinoid syndrome
Rheumatoid arthritis
Ulcerative colitis
Multiple myelomas, leukemias, Waldenstrom’s macroglobulinemia
Autoimmunity (systemic lupus, collagen diseases)
Kidney dysfunction (nephrosis)

Question 11

Serum globulin level may decrease in

Answer 11

-Nephrosis (a condition in which the kidney does not filter the protein from the blood and it leaks into the urine)
-Alpha-1 Antitrypsin Deficiency (Emphysema)
-Acute hemolytic anemia
-Liver dysfunction
-Hypogammaglobulinemia/Agammaglobulinemia

Question 12

What is the theory of refractometry?

Answer 12

Method is based on refraction of incident light by dissolved solids. The refractive index of water at 20 C is 1.3330. The refractive index increases proportionally with increasing amounts of a particular solute

Question 13

What are major interfering substances in the determination of serum protein by refractometry?

Answer 13

Lipemia and hemolysis may cause falsely increased plasma protein values.

Question 14

Name three ways to separate albumins from globulins.

Answer 14

1.Gel electrophoresis
2.Column Chromatography
3.Ultracentrifugation
4.Others: precipitation, plasma fractionation

Question 15

Prealbumin is normally present in what substance undergoing electrophoresis?

Answer 15

Prealbumin normally present in CSF but not in serum

Question 16

What significance does glucose in spinal fluid provide?

Answer 16

It can help differentiate a viral infection from a bacterial infection. In bacterial infection glucose levels are decreased while in viral infection glucose does not decrease.

Question 17

What is the normal range of glucose in spinal fluid?

Answer 17

50 - 80 mg/dL or approximately 2/3 of blood sugar levels

Question 18

Meningitis is present in a patient. What would their spinal fluid tests look like?

Answer 18

A bacterial meningitis would have increased CSF protein and decreased CSF glucose with a high number of neutrophils.
A viral meningitis would have normal CSF protein levels and normal glucose levels with a high number of lymphocytes.