Amino Acids, Proteins and Non-Protein Nitrogen Compounds

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1

peptide bond

a chemical bond formed between the carboxyl group of one amino acid and the amino group of another

2

oligopeptide

amino acids combined into chains up to five

3

polypeptide

longer chains of 6-39 amino acids

4

protein

greater than 40 chains of amino acids

5

essential amino acids

10 amino acids that must be supplied by food; 10 can be synthesized by the body

6

aminoacidopathies

rare inherited disorders of the amino acid metabolism

7

Guthrie Test

tests for metabolic disorders

8

protein characteristics

measured in g/dL found in high amounts 50-70% of cell's dry weight; contain carbon, hydrogen, oxygen, nitrogen and some sulfur; synthesized in the liver

9

protein function

maintain osmotic pressure and water distribution, support collagen and keratin, transports molecules, enzymes, peptide hormones (insulin), coagulation, hemoglobin, and antibodies

10

total protein

sum of all proteins found in the serum/plasma made up of albumin and globulins

11

prealbumin

synthesized mainly in the liver; migrates ahead of albumin on electrophoresis; transports protein for thyroid hormones and retinol

12

decreased albumin

hepatic damage, acute-phase inflammatory responses, tissue necrosis, and poor nutrition

13

increased albumin

steroid therapy, alcoholism, and chronic renal failure

14

albumin

synthesized in the liver; highest concentrated plasma protein; maintains colloid osmotic pressure, buffers pH, negative acute phase reactant, and binds blood substances

15

decreased albumin

malnutrition/malabsorption (inadequate amino acid intake), liver disease, GI loss (fluid loss), renal disease (excessive excretion), dilution by excess (IV fluids, polydipsia)

16

increased albumin

dehydration and excessive infusion

17

a1-globulins

a1-antitrypsin and a1-acid glycoprotein

18

a1-antitrypsin

the major a1 globulin (90%); acute phase reactant with anti protease activity resulting in the neutralization of leukocyte elastase and collagenase

19

A1-antitrypsin deficiency

one of the most common genetically lethal diseases in Caucasians (1:4000); early onset emphysema in the absence of smoking; juvenile hepatic cirrhosis

20

a1-acid glycoprotein

the major glycoprotein increased during inflammation

21

a1-acid glycoprotein increase

found in rheumatoid arthritis, cancer, pneumonia, and other conditions resulting in APR

22

a-2 globulins

includes haptoglobin, ceruloplasmin, and a2-macroglobulin

23

haptoglobin

acute phase reactant; binds hemoglobin

24

ceruloplasmin

acute phase reactant; redox activity; 90% copper found here

25

a2-macroglobin

inhibits proteases

26

increased haptoglobin

inflammatory diseases; rheumatic disease

27

increased ceruloplasmin

inflammation, severe infection, tissue damage, pregnancy, and others

28

increased a2-macroglobin

nephrosis, diabetes, and liver disease; nephrotic syndrome, estrogen intake and slightly in diabetes mellitus

29

decreased haptoglobin

hemolytic anemia and liver disease

30

decreased ceruloplasmin

Wilson's disease, malnutrition, malabsorption, severe liver disease, and others

31

nephrotic syndrome

characteristically increased a2-macroglobin up to 10 times normal because it is retained while smaller proteins are excreted in urine

32

Wilson Disease

a rate autosomal recessive trait where Cp levels are reduced and the dialyzable Cu concentration is increased; excessive Cu in liver, kidney, and brain leads to degenerative cirrhosis, chronic acute hepatitis, renal tubular acidosis, and neurological damage (clumsiness and tremors) unless treated with copper chelator

33

Cp

acute phase reactant that increases late in Wilson's Disease

34

B-Globulins

transferrin, hemopexin, lipoprotein, fibrinogen, complement, and C-reactive protein

35

transferrin

transports iron, prevents iron loss, and negative acute phase reactant

36

increased transferrin

IDA

37

decreased transferrin

liver disease, nephrotic syndrome, and malnutrition

38

hemopexin

acute phase reactant and binds free heme

39

increased hemopexin

inflammation, diabetes mellitus, and melanoma

40

decreased hemopexin

hemolytic anemia

41

lipoprotein

transports lipids, mainly LDL

42

increased lipoprotein

atherosclerosis, heart disease, diabetes mellitus, and hypothyroidism

43

fibrinogen

precursor of fibrin clot

44

increased fibrinogen

acute phase of inflammatory processes, pregnancy, and oral contraceptives

45

decreased fibrinogen

excessive coagulation

46

complement

immune response

47

increased complement

inflammation

48

decreased complement

malnutrition and hemolytic anemia

49

CRP

acute phase reactant

50

increased CRP

tissue necrosis and cardiac disease

51

B2-microglobulin

a low-molecular-weight protein that comprises the common light chain of class 1 major histocompatibility complex (MHC) antigens found in all nucleated cells

52

Beta-2 microglobulin increase

renal failure, inflammation, and neoplasms (especially those associated with B-lymphocytes

53

y-Globulins

immunoglobulins/antibodies

54

IgG

gamma; anamnestic antibody response; molecular weight of 150,000, most abundant in serum; respond to most bacteria and viruses

55

increased IgG

liver disease, infections, parasitic disease, and others

56

decreased IgG

immunodeficiency and others

57

IgA

alpha; antibodies in secretions; molecular weight of 160,000, 10-15%; found in tears, sweat, saliva, milk, and GI and bronchial secretions

58

increased IgA

liver disease, infections, and autoimmune disease

59

decreased IgA

immunodeficiency and decreased protein synthesis

60

IgM

mu; early response antibodies; largest molecular weight of 900,000, 5-10% of Its

61

increased IgM

toxoplasmosis and others

62

decreased IgM

hereditary immunodeficiency

63

IgD

delta; antibody

64

increased IgD

infections and liver diesease

65

IgE

epsilon; antibodies to allergens, urticaria, hay fever, and asthma; molecular weight of 180,000, very low concentrations micrograms/mg

66

increased IgE

not diagnostic

67

troponin

heart marker for MI

68

BNP

distinguishes between MI and CHF

69

fibronectin

glycoprotein used to predict the short term risk of premature delivery

70

hypoproteinemia

total protein less than 6.4 g/dL caused by excessive loss (blood, burns, renal disease), decreased intake (malnutrition or malabsorption), decreased synthesis (liver disease or immunodeficiency), or acceleration of protein catabolism (burns, trauma)

71

hyperproteinemia

total protein greater than 8.3 g/dL; caused by dehydration (excess water loss from vomiting, diarrhea, inadequate intake, etc.) or excessive production of gamma globulins (multiple myeloma and Waldenstrom's)

72

Biuret

total protein methodology based on presence of peptide bonds found in all proteins; protein treated with cupric divalent ions in moderately alkaline medium, a violet colored chelate absorbs light formed between cupric ion and carbonyl oxygen and the amide nitrogen atoms of the peptide bond

73

biuret reagent

sodium potassium tartrate; complexes with cupric ions to prevent their precipitation in alkaline solution; major reactant is copper sulfate; potassium iodide: antioxidant stabilizing cupric ions and NaOH provides alkalinity

74

6.5-8.2 g/dL

serum protein in healthy, ambulatory adults

75

0.5 g/dL

expected protein decrease in bed-ridden patients

76

non-protein nitrogen compounds

traditionally used to monitor renal function; not proteins or polypeptides; useful in monitoring individual components; derived from catabolism of proteins and nucleic acids; creatinine, urea nitrogen, etc.

77

clinically significant NPNs

urea, uric acid, creatinine, and ammonia, and amino acids and creatine

78

BUN

blood urea nitrogen;

79

urea

converted in the liver from ammonia and CO2; filtered by the glomerulus, reabsorbed by renal tubules, some lost through the skin and GI tract

80

urea measurement

evaluate renal function, assess hydration status, determine nitrogen balance, aid in diagnosis of renal disease, and monitor dialysis treatment

81

6-20 mg/dL

reference values urea nitrogen in plasma

82

12-20 mg/dL

reference values urea nitrogen in urine

83

azotemia

elevated plasma BUN

84

prerenal azotemia

increased BUN not related to renal function; hypotension (CHF, shock, hemorrhage, dehydration), decreased blood flow to kidney (no filtration), and increased dietary protein or protein catabolism (fever, major illness, stress)

85

prerenal decreased BUN

not related to renal function; decreased dietary protein, increased protein synthesis (pregnancy, childhood)

86

renal azotemia

causes of increased BUN; acute and chronic renal failure, glomerular nephritis, tubular necrosis, intrinsic renal disease

87

uremia/uremic syndrome

very high urea levels plus renal failure

88

post renal azotemia

causes of increased BUN not related to kidney function; obstruction of urine flow caused by kidney stones, bladder or prostate tumors, and UTIs

89

dialysis

treatment for uremia or end stage renal disease

90

Urea Reduction Ratio

Predialysis BUN-Postdialysis BUN/Predialysis BUN * 100

91

adequate dialysis

URR greater than 60%

92

BUN/Creatinine Ratio

Blood Urea Nitrogen to Creatinine Level

93

10-20 to 1

normal BUN/Creatinine ratio

94

Pre-renal BUN:C

increased ratio; BUN more susceptible to non-renal factors; increased BUN/Normal Creatinine

95

Renal BUN:C

increased ratio due to elevated BUN and elevated Creatinine

96

Post-renal BUN:C

increased ratio; increased BUN and slightly increased Creatinine

97

2.14 (60/28)

factor to convert urea nitrogen concentration to urea concentration

98

molecular weight of BUN and Nitrogen

the conversion factors used to convert Urea to Urea nitrogen

99

0.467 (28/60)

factor used to convert from urea to urea nitrogen by dividing the molecular weight of nitrogen by the molecular weight of urea

100

Berthelot's Reaction

Urea + 2H2O ---> (urease) 2NH4^+ + CO3^-2

101

creatine

synthesized mainly in the liver from arginine, glycine, and methionine then transported to other tissues and converted to creatine phosphate, a high energy source; not affected by diet

102

elevated creatinine

associated with abnormal renal function, especially related to decreased glomerular function in plasma, indicating renal damage

103

elevated creatine

associated with muscle disease: muscular dystrophy, poliomyelitis, hyperthyroidism, trauma, etc; not associated with renal disease

104

clinical applications of creatinine

determines sufficiency of kidney function and severity of kidney damage and monitor progression of kidney disease

105

creatinine clearance

measure of rate at which creatinine is eliminated from blood by kidneys; measurement of glomerular filtration

106

glomerular filtration rate (GFR)

volume of plasma filtered by glomerulus per unit of time

107

0.6-1.1 (53-97) mg/dL

Jaffe plasma creatinine intervals for women

108

0.9-1.3 (80-115) mg/dL

Jaffe plasma creatinine intervals for men

109

Creatinine Clearance Equation

U X V/P

Urine Concentration (mg/dL) times Plasma Concentration (mg/dL) all divided by Urine Flow (mL/minute [1440min/24hr]) X 1.73 m^2 / BSA m^2 (normalization factor)

110

97-137 mL/min

creatinine clearance reference range for males

111

88-128 mL/min

creatinine clearance reference range for females

112

90-130 mL/min

creatinine clearance reference range

113

uric acid

product of catabolism of purine nucleic acids; most reabsorbed in proximal tubules and reused; relatively insoluble in plasma; deposited in joints and tissues in high concentration leading to inflammation

114

purines

converted to uric acid in the liver then transported to kidney and filtered by glomerulus; 70% eliminated by renal excretion, remainder passes into GI tract degraded by bacterial enzymes

115

gout

primarily in men 30-50 years; UA greater than 6.0 mg/dL; pain and inflammation of joints by precipitation of sodium rates in tissues; increased risk of renal calculi; hyperuricemia due to overproduction of uric acid in 25-30%

116

increased catabolism

occurs in patients on chemotherapy for diseases such as leukemia and multiple myeloma

117

chronic renal disease

causes elevated levels of uric acid because filtration and secretion are hindered

118

hypouricemia

secondary to severe liver disease; defective renal tubular reabsorption (Fanconi's syndrome); chemotherapy with 6-mercaptopurine or azathioprine - inhibit purine synthesis

119

3.5-7.2 mg/dL

uric acid plasma reference interval for males

120

2.6-6.0 mg/dL

uric acid plasma reference range for females

121

250-750 mg/dL

uric acid 24 hour urine reference range

122

ammonia

comes from deamination of amino acids; digestive and bacterial enzymes in intestine; released from muscle during exercise; consumed by parenchymal cells of liver and converted to urea; free is toxic, but present in plasma in low concentration

123

elevated ammonia levels

not removed from circulation and not converted to urea due to liver disease; elevated levels are neurotoxic and often associated with encephalopathy

124

Reye's Syndrome

most commonly seen in children; often preceded by viral infection treated with aspirin; severe fatty infiltration of liver; may be fatal if ammonia levels remain high; 100% survival if ammonia stays below 5x normal

125

glutamate dehydrogenase

decrease in absorbance at 340 as NADPH is consumed (oxidized)

126

Direct ISE

change in pH of solution as ammonia diffuses through semi-permeable membrane

127

19-60 micrograms/dL

glutamate dehydrogenase reference intervals in adult plasma

128

protein denaturation

heat, pH changes, mechanical forces, chemical exposure, and ultraviolet light exposure

129

electrophoresis

the migration of charged solutes or particles in a liquid medium under the influence of an electrical field

130

alkaline environment

proteins will assume a net negative charge (anions) and migrate towards the anode

131

cations

positive ions that migrate towards the cathode

132

cathode

the negative pole

133

anode

the positive pole

134

anions

the negative ions that migrate towards the anode

135

positive acute phase proteins

acute phase reactants that increase during inflammation; a1 proteins, a2 proteins, and b proteins

136

negative acute phase proteins

albumin, transferrin, and transthyretin (prealbumin)

137

acute phase reaction increases

infection, tumor growth or malignancy, rheumatoid arthritis, hepatitis, surgery, trauma, burns, and myocardial infarction

138

nephrotic syndrome

characterized by a decrease in albumin and gamma globulin bands in conjunction with an increase in a2-globulins suggesting proteinuria;

139

monoclonal gammopathies

antibody proteins which are produced by normal plasma cells

140

multiple myeloma

a cancer of the plasma cells in the bone marrow causing them to produce abnormal M proteins; large peak (M spike)

141

SPEP

used to separate and identify the presence and levels of M protein in the blood

142

polyclonal gammopathy

gamma zone is elevated fairly broadly indicating more than one type of gamma globulin present and increased

143

Beta gamma bridging

result of fast moving gamma globulins that prevent resolution of beta and gamma globulins

144

cirrhosis

the most common cause of beta-gamma bridging; low albumin, alpha 1 and alpha 2; increased gamma globulins

145

autoimmune hepatitis

decreased albumin and increased polyclonal IgG

146

primary biliary cirrhosis

increased polyclonal IgM

147

hypogammaglobulinemia

the gamma zone/peak very low; decrease in gammaglobulins in blood; immunosuppressed patients; elevations in alpha 2 zone due to acute phase reactants which elevate during bacterial infections

148

SD

the square root of the sum of each (statistic minus the mean) squared all over the number of factors minus 1

149

Base Units

Femto, Pico, Nano, Micro, Milli, Centi, Deci, (Base), Deca, Hecto, Kilo, Mega, Giga, Tera

150

Molarity

Moles of Solute per liter of solution

151

Normality

Equivalent weight per liter; Molarity times the number of ions in the acid

152

Equivalent Weight

gram molecular weight divided by valence

153

Internal QC

daily, reference ranges, validation, instrument repair

154

External QC

proficiency testing

155

CV

Standard Deviation divided by the Mean times 100

156

shift

6 consecutive data results on the same side of the mean

157

trend

a consistent increase or decrease in data points over 6 day period

158

Planck's Formula

E=hf

Energy of a photon = constant times frequency

159

Beer's Law

A=abc

Absorbance = absorptivity x path length of cell (cm) x concentration