Proteins Wk 2

Question 1

What is the primary protein structure

Answer 1

Linear amino acid sequence
All have this

Question 2

What is the secondary protein structure

Answer 2

Alpha helix, beta sheets and random coil

Question 3

What is the tertiary protein structure

Answer 3

3D, globular and fibrous

Question 4

What is the quaternary structure

Answer 4

Not all proteins have this
Multi protein assemblies

Question 5

What are examples of extra functional prosthetic groups or ligands on proteins

Answer 5

VDL, HDL, transferrin, lipoproteins

Question 6

What is the amino acid configuration of biological relevant ones

Answer 6

L configuration

Question 7

What is a zwitterion

Answer 7

Dipolar
Depends on solution pH, most amino acids are in this form at physiological pH7.4

Question 8

Are amino acids water soluble

Answer 8

Most are

Question 9

How many proteins are in plasma

Answer 9

3500 types

Question 10

Main functions of proteins

Answer 10

Transporting other molecules (Hb, transferrin)
Structural (collagen, keratin)
Regulatory WIRH enzymes
Hormonal (insulin)

Question 11

What is the most abundant protein

Answer 11

Albumin
Maintains blood pressure in blood vessels

Question 12

What is total protein

Answer 12

All the protein in plasma, heterogenous with different charges/physical characteristics

Question 13

What is total protein measured? What is the method called

Answer 13

Biuret method
Spectrophotometry

Question 14

What to consider when choosing analytical methods

Answer 14

Analyte size/charge/structure
How it interacts with light
Potential interferences
Do you want quantitative or qualitative
Tech available
Cost

Question 15

What is spectroscopy

Answer 15

Study of how energy and matter interact

Question 16

What is spectrometry

Answer 16

The practical application of spectroscopy

Question 17

Spectrophotometry

Answer 17

The measurement of light spectra as presented as a wavelength

Question 18

What does beer lambert law mean

Answer 18

Where linearity exists absorbance and concentration are directly proportional

Question 19

Visible light is between what wavelength size

Answer 19

700nm -400 nm

Question 20

What makes something appear a certain colour

Answer 20

If it absorbs the opposite colour

Question 21

If the substance absorbs red what colour do you see

Answer 21

Blue-green

Question 22

Total protein absorbs green light so you see

Answer 22

Purple

Question 23

What is the chemistry behind the biuret method

Answer 23

Strong alkaline solutions have copper ions that form complexes with peptide bonds, this changes it’s wavelength causing a colour change from blue to purple

Question 24

What wavelength was TP measured at

Answer 24

540nm

Question 25

If you see purple in biuret reaction what does this mean in terms of the other colours

Answer 25

All colours except violet is absorbed by the sample and violet is reflected or red/blue/violet is reflected

Question 26

What are some potential interferences for the biuret method

Answer 26

anything with an absorbance at 540nm Haemolysis causes interference as Hb as a similar absorbance maxima and lots of proteins are released which also interfere

Question 27

What does the buffer do in electrophoresis

Answer 27

Carries the current and controls the pH

Question 28

Why is it important to regulate the buffer and so the pH

Answer 28

pH determines The rate of migration, which electrode the solute migrates too, the sharpness of the zones, the electrical charge of the solute

Question 29

What is different between the capillary electrophoresis and gel

Answer 29

Capillary is automated and faster with better separation and higher voltage capacity on a much smaller sample size

Question 30

Is albumin negatively charged or positive

Answer 30

Negative, high peak at positive cathode as most abundant

Question 31

Where is albumin made

Answer 31

In the liver

Question 32

Half life of albumin

Answer 32

15-19 days

Question 33

Functions of albumin

Answer 33

Maintaining oncotic pressure Transporter Antioxidant activity

Question 34

How is albumin measured

Answer 34

Using dye binding as at low pH it will react with anionic dyes like green BCG and purple BCP

Question 35

What is albumin rich in

Answer 35

An anionic protein enriched in Asp and Glu

Question 36

Is binding for albumin specific using BCG or BCP

Answer 36

No because other proteins have Asp and Glu so read absorbance within 30s to increase specificity

Question 37

Can you measure albumin using binding dyes in any sample type

Answer 37

Yes you can use plasma/serum/urine

Question 38

BCG wavelength

Answer 38

630

Question 39

BCP wavelength

Answer 39

600nm

Question 40

Reasons for hyperalbuminemia

Answer 40

Dehydration Tourniquet left on Of no significance

Question 41

Reasons for hypoalbuminemia

Answer 41

Pregnancy dilutes it Malignancy Infection Inflammation Loss from kidney disease in urine Loss from GI disease Less production of albumin from liver failure, chronic inflammation and nutritional deficit

Question 42

What is seen in analbuminaemia

Answer 42

Edema Low BP Fatigue Hypercholesterolemia High LDL Lower body lipidystrophy

Question 43

Bisalbuminaemia

Answer 43

2 types of albumin Two peaks in electrophoresis Rare - can be transient or inherited

Question 44

What proteins are found in the alpha 1 region of electrophoresis

Answer 44

Alpha 1 antitrypsin / fetoprotein/ acid glycoprotein AAT AFP

Question 45

What proteins are in the alpha 2 region

Answer 45

Haptoglobin Cp Macroglobulin

Question 46

When is Cp reduced

Answer 46

Wilson’s disease - excess Cu deposited in tissues and it’s role is to transport copper

Question 47

What is macroglobulin

Answer 47

A protease inhibitor Largest non Ig protein in plasma Inhibits thrombin

Question 48

When does macroglobulin is alpha 2 region increase

Answer 48

In nephrotic syndrome

Question 49

When do globulins increase

Answer 49

In inflammation, renal disease, and malignancy

Question 50

What is found in the beta protein region

Answer 50

Transferrin Microglobulin BMG C3 and C4 - complement

Question 51

When do complement proteins C3 and C4 decrease

Answer 51

Genetic deficiencies

Question 52

When do complement C3 and C4 increase

Answer 52

Inflammation

Question 53

Where is B2 Microglobulin found

Answer 53

In urine, small amounts as it’s small and can be filtered

Question 54

When is B2 Microglobulin increased

Answer 54

In renal failure - this can be filtered but should be reabsorbed Inflammation Neoplasia

Question 55

Gamma region proteins

Answer 55

CRP Immunoglobulins

Question 56

When does CRP increase

Answer 56

Inflammation Infection Trauma

Question 57

How are immunoglobulins measured

Answer 57

Doing an immunoassay

Question 58

When do immunoglobulins increase

Answer 58

Malignancy - monoclonal gammopathy Polyclonal hyperimmunoglobulinaemia

Question 59

Highly sensitive CRP increase =

Answer 59

Associated with increased CVD risk

Question 60

What are monoclonal immunoglobulins

Answer 60

Paraproteins

Question 61

What is an increase in Paraproteins associated with

Answer 61

Proliferation B cell disorders As Paraproteins are free light chains which are made by plasma cells Can be a plasma cell myeloma

Question 62

Where are free light chains found

Answer 62

In the urine in myeloma

Question 63

What is AFP and when is it screened

Answer 63

Alpha 1 fetoprotein Screening in fetal abnormalities

Question 64

When is AFP elevated

Answer 64

Metastatic liver disease Tumours in ovary and testis

Question 65

Where is A1 acid glycoprotein made

Answer 65

Liver It is an acute phase protein

Question 66

How is alpha 1 antitrypsin measured

Answer 66

EP - screening Immuniturbidimetry Nephelometry

Question 67

When do you get a decrease in AAT

Answer 67

Pulmonary emphysema Cirrhosis

Question 68

Where is AAT made

Answer 68

Liver Inactivates trypsin