Lesson 3. COMPLEX (CONJUGATED) PROTEINS: GLYCOPROTEINS, LIPOPROTEINS, AND PHOSPHOPROTEINS. QUANTIFICATION OF PROTEINS

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Task

Guidelines for performing the task

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2

3

1

Study the classification, structure and chemical properties of carbohydrates

1. Write down the formula of α-D-glucose, α-D-fructose, N-acetyl galac-tosamine, neuraminic acid

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2

Study the structure, properties and biological significance of various representatives of glycoproteins

1. Identify O- and N-glycosidic bonds between protein and carbohydrate components in molecules of glycoproteins.

2. Give examples of glycoproteins that perform the function of enzymes, hormones, blood clotting factors, transporters.

3. Characterize the structure and biological role of mucosal glycopro-teins - salivary mucin, gastromucoprotein, uroglycoproteins

3

Study the classification, structure and biological role of proteoglycans

1. Write down the classification of glycosaminoglycans. Write down the structure of disaccharide units for hyaluronic acid, chondroitin sulfate, keratin sulfate, dermatan sulfate, heparan sulfate.

2. Make a schematic drawing of proteoglycan complexes of extracellular fluid. Describe the role of hyaluronic acid in the extracellular matrix.

3. List the physico-chemical features of proteoglycan complex

4

Recall the structure of lipids

1. Describe the classification of lipids.

2. Write down the general formula of triacylglycerols (TAG), give examples of simple (triolein) and mixed (stearooleipalmitin) triacylglyc-erols. How does different fatty acid composition affect physico-chemical properties of TAG?

3. Remember the structure of phosphoglycerols - posphatidic acid, posphatidyl choline, posphatidyl ethanolamine, phosphatidyl serine.

4. What does plasmalogens mean?

5. Remember the structure of sphyngolipids - sphingomyelins, cere-brosides, gangliosides.

6. Remember the structure of cholesterol and cholesterol esters

5

Study the structure, chemical composition, methods of separation and biological role of blood serum lipoproteins

1. Make a schematic drawing of blood serum lipoprotein structure. Which methods are used to separate plasma lipoproteins?

2. What is the function of blood serum lipoproteins?

3. Fill the table to characterize the difference between chemical composition of different types of blood serum lipoproteins (see below)

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Study the structure and function of biological membranes

1. Characterize the chemical composition of biological membranes. Make a schematic drawing of the structure of biological membranes.

2. Characterize liquid-crystal structure of biological membranes.

3. Describe the types of transmembrane transport of substances.

4. What does liposome mean? How can they be used in medicine?

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Study the structure of phosphopro-teins

1. Characterize the bond between apoprotein and phosphoric acid residue.

2. Give examples of most common phosphoproteins and describe their significance

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8

Study the methods of quantitative analysis of proteins in biological fluids

1. Formulate the principle of quantitative analysis of protein by biuret method.

2. Point out the reference level of protein in the blood and give examples of diseases associated with hypo- and hyperproteinemia

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Study the dependence between light absorption and intensity of solution color

1. Draw the graph of dependence of light absorption on intensity color of the solution.

2. Make a schematic drawing of photocolorimeter and briefly describe the principle of protein quantification in solution

10

Study the principle of protein fraction-ation by electrophoresis

1. What does electrophoresis mean? Explain why various proteins move in electric field at a different rate. Formulate the principle of electropho-resis in protein fractionation.

2. Describe the main protein fractions of the blood.

3. Describe the significance of determining protein spectrum of the blood in medicine

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Study the principle of protein fractionation by ion-exchange chromatography

1. What does ion-exchange chromatography mean?

2. Formulate the principle of ion-exchange chromatogramphy in protein fractionation

Type of lipoproteins

Reference level in the blood, g/l

Apoprotein,

%

TAGs,

%

Cholesterol,

%

Phospholipids,

%

(chylomicrons

VLDL

(pre-ß-lipoproteins)

LDL

(ß-lipoproteins)

HDL

(α-lipoproteins)

Reference standard solutions

1

2

3

4

5

Protein content (mg)

20

40

60

80

100

Protein concentration (g/l)

20

40

60

80

100

Analytical standard solution of protein (ml)

0.2

0.4

0.6

0.8

1.0

Water (ml)

0.8

0.6

0.4

0.2

0