Exam 6: Proteins/Liver Function/Nonprotein nitrogen Flashcards
What is the primary structure of a protein?
Sequence of amino acids
What is the secondary structure of a protein?
Formation of a helix
What is the tertiary structure of a protein?
Folded 3D protein structure
What is the quaternary structure of a protein?
Two or more peptide chains integrated
What two enzymes digest dietary proteins?
Pepsin and trypsin
PKU: cause, urine characteristics
Buildup of phenylalanine in the blood causes urine to have a musty/mousy odor
What is the Guthrie test?
Used to detect PKU; if elevated levels of phenylalanine are found in the blood on the filter paper, bacteria will grow on agar plate
What can tyrosinemia lead to?
liver damage
Alkaptonuria
Accumulation of homogentisic acid turns urine black colored
Maple Syrup Urine Disease
Blocks normal metabolism of leucine, isoleucine, and valine that causes urine to smell like maple syrup
What is a proteins isoelectric point?
The pH at which an amino acid or protein has no net charge
Most proteins are synthesized in the ______.
liver
What are some functions of proteins?
Tissue nutrition
Maintain oncotic pressure
Act as buffers to maintain pH
Transportation of metabolic substances
Immunity (antibodies)
Hormones and receptors
Structure (connective tissue)
Enzymes
Coagulation and hemostasis
What fraction does prealbumin migrate to in electrophoresis and what is its function?
Just ahead of albumin - rarely distinguished from albumin band. Prealbumin transports the thyroid hormones T3 and T4 and Retinol (vitamin A)
What fraction does albumin migrate to in electrophoresis and what is its function?
It is the first large peak (band). This is the protein in highest concentration in the blood.
It binds and transports materials in the bloodstream and maintains oncotic pressure/fluid balance in tissues.
Analbuminemia vs bisalbuminemia
Do not produce any albumin vs produces two types of albumin
What fraction does alpha-1 antitrypsin migrate to and what is its function?
Alpha-1 Globulins
Functions to neutralize enzymes that cause damage to structural protein in the lungs
What fraction does alpha-1 fetoprotein migrate to and what is its function?
Alpha-1 Globulins
Synthesized by fetal yolk sac - Useful for screening for any conditions where fetus produces excess proteins or insufficient proteins and useful for tumor markers
What fraction does haptoglobin migrate to and what is its function?
Alpha-2 Globulins
Functions to bind free hemoglobin
What fraction does ceruloplasmin migrate to and what is its function?
Alpha-2 Globulins
Contains 90% of body’s copper and has enzymatic activities
What is Wilson’s disease and what protein is used to help diagnose it?
Inherited disorder where copper is deposited in the skin, liver, cornea, and brain presenting with low ceruloplasmin levels
What fraction does Alpha-2 Macroglobulin migrate to and what is its function?
Alpha-2 Globulins
Inhibits proteases such as trypsin, thrombin, kallikrein, and plasmin
What fraction does Transferrin migrate to and what is its function?
Beta-Globulins
Functions to transport iron
What fraction does C-Reactive Protein migrate to and what is its function?
Beta-Globulins
Elevated in situations of inflammation, used as a risk factor for cardiovascular disease
What fraction do immunoglobulins migrate to and what are their function?
Gamma Globulins
Synsthesized by plasma cells associated with immune system
What protein, if detected on protein electrophoresis, could tell us that plasma was submitted instead of serum?
Fibrinogen - present as a distinct band between beta and gamma regions on plasma electrophoresis - WILL NOT be present in serum
What is considered the reference method for total protein measurement?
6.5-8.3 g/dL in serum
What are some causes of hypoproteinemia?
Excessive protein loss
Decreased Intake
Liver disease
Inherited immunodeficiency disorder
Accelerated catabolism of proteins