C11 Amino Acids & Proteins Flashcards
Proteins
single most important group of organic compounds associated with living organisms
Lipids
water insoluble fatty molecules- require proteins in order to be transported through the plasma…lipoproteins
Amino acids
building blocks of proteins
DNA
very large molecule that contains biochemical codes to make proteins from amino acids
Genomics
study of DNA
Genome
all the DNA in a living organism
Nucleotides
2 purine bases (adenine and guanine)
2 pyrimidine bases (cytosine & thymine)
Adenine bonds with?
Thymine
Guanine bonds with?
Cytosine
Three groups of consecutive bases that provide the code for an amino acid?
codon
Sequence of DNA that provides the code for an entire protein?
Gene
When cells divide, the DNA condenses in visible structures called?
chromosomes
Each nucleated cell has 23 pairs of chromosomes, each representing a pair of DNA molecules which are joined at a central?
centromere
Human DNA contains how many genes?
20-25,000
DNA provides a code for the creation of?
mRNA
How is mRNA created?
actions of RNA polymerase and a promoter protein (Transcription)
What is translation?
When mRNA goes into the ribosomes where it meets up with individual amino acids and assembles them together to create proteins
What are DNA or NAT probes?
lab techniques that allow for the detection of specific nucleotide sequences
Advantages of DNA probes and NAT?
extremely specific, sensitive, and faster than routine culture
Disadvantages of DNA probes and NAT?
extreme sensitivity can cause problems if contaminated with outside sources, difficult and expensive techniques
All proteins are composed of?
amino acids
How many naturally occurring amino acids are there?
20
Aminoacidopathies?
uncommon, inherited, genetic disorders of amino acid metabolism
Most common aminoacidopathy?
Phenylketonuria (PKU)
Phenylketonuria
autosomal recessive (requires 2 defective genes from both parents), absence of phenylalanine hydroxylase… si cannot be converted to tyrosine, it accumulates and is converted to phenylpyruvic acid (which is toxic to newborns and kids resulting in brain damage and mental retardation) damage begins 2-3 wks after birth, treated with dietary restrictions
Guthrie Test
Small disk of filter (PKU) paper is punched out and placed on agar plate containing Bacillus subtillis & B2 thienylalanine, the agar gel is able support bacterial growth but B2 thienylalanine inhibits it, though with extra phenylalanine bacteria can grow, growth is proportional to amount of phenylalanine in serum
Primary (Protein conformation)
amino acid sequence
Secondary (protein conformation)
winding, twisting of the amino acid chain, regulated by hydrogen bonding between different locations on the chain
Tertiary (protein conformation)
3D structure of the amino acid chain, regulated by chemical interactions between the “R” groups
Quaternary (protein conformation)
non-covalent bonding between 2 or more polypeptide chains
Amino acids are linked together by a special type of chemical bond called?
peptide bond
A peptide bond occurs between a __ and a ___ of another?
carboxyl group of one amino acid, amino group
Whenever 2 amino acids are linked together with a peptide bond, what molecule is produced?
water
amphoteric
may have a + or - electric charge
Most proteins are synthesized in?
the liver
Immunoglobulins are synthesized in?
B-lymphs
3 sources of amino acids?
digestion and absorption, synthesis by liver, and re-utilization from protein catabolism
How many of the 20 amino acids can be synthesized by the liver and how many must be ingested?
11 are synthesized, 9 must be ingested
Peptide chains composed only of amino acids?
simple proteins
composed of a protein fraction and a non protein fraction?
conjugated proteins
lipoproteins
protein+lipid
glycoprotein
protein+carbohydrate
nucleoprotein
protein+nucleic acids
General functions of proteins:
energy source, contribute to osmotic pressure, act as buffers, transport molecules, coagulation/hemostasis, immune function, hormones and hormone receptors, structural molecules
Prealbumin
migrates ahead of albumin, decreased amt indicated poor nutrition, 15-40 mg/dl
Albumin
highest concentration of proteins, 80% of tissue osmotic pressure, major transport and binding protein, decreased amt associated with poor nutrition, liver, and renal disease
Alpha-1-Anti-Trypsin
Migrates in Alpha1 band, acute phase reactant, decreased amt associated with pulmonary disease
Alpha-1-Fetoprotein
Migrates between alpha1 and albumin band, synthesized in yolk sac and liver during gestation decreases after birth, increased: spina bifida, neural tube defects, twins, hepatocellular cancer, decreased: down syndrome and trisomy 18
Haptoglobin
Alpha 2, binds free hemoglobin, preventing loss in urine,, increased: inflammatory conditions, decreased: intravascular hemolysis
Transferrin
Beta, iron transport protein, increased with iron deficiency, decreased with anemia
Hemopexin
beta, acute phase reactant, bind free heme and transports it to liver
Complement
activated can lyse cells, C3 and C4 most abundant, increased in acute inflammatory conditions, decreased in chronic autoimmune disorders (RA and LE)
C-Reactive Protein (CRP)
Gamma, increased in infection, gout, autoimmune disease, cancers, tissue necrosis, early indicator for CVD and Type 2 diabetes
hs-CRP (high sensitivity)
high CRP in lower survival post AMI and arterial re-closure post balloon angioplasty,
Immunoglobulins
gamma, each antibody has 2 heavy & 2 light chains, antibody specificity determined by variable region at end of heavy & light chains, light chains are kappy lambda, multiple myeloma produces large concentrations of a single class of IgG, Waldenstrom’s disease produces IgM
IgG
increased in chronic infections
IgM
increased with acute infections
IgE
associated with parasitic infections & allergic immune reactions
IgA
found in secretions
Myoglobin
heme protein found in skeletal & cardiac muscle, AMI, elevated 1-3hrs post AMI, peaks at 5-12hrs post AMI, returns to normal by 18-30hrs, also elevated in crush injuries & renal failure 30-90ng/ml
Troponin
complex of 3 proteins that regulate muscle contraction in cardiac & skeletal muscle, associated with cardiac tissue & is useful to evaluate possible AMIs, elevated 3-4hrs post AMI, peaks 10-24hrs post AMI, remains elevated 10-14 days, single best test for the diagnosis of AMI <.06ng/ml
B-Type Natriuretic Peptide (BNP)
hormone the heart releases in response to increased heart pressure associated with CHF, increased BNP causes arterial and venous vasodilation, suppression of aldosterone and promotes diuresis (decreases bp) 0-100pg/ml
Actue Phase Proteins (Reactants)
Positive-increased concentration during inflammation
Negative-decreased concentration during inflammation
Hypoprotenemia
below normal TP indicates a negative nitrogen balance, decreased protein synthesis, increased protein loss
Hyperprotenemia
excessive protein synthesis, dehydration
Kjedahl Method for Total Protein
classic reference method used to standardize all other techniques (technically difficult, labor intensive, and expensive) based upon measurement of total nitrogen and the following relationship between nitrogen and protein (16%)(Total Nitrogen)=(Total Protein)
No longer done routinely!
Biuret Method for Total Protein
** most common technique, all proteins have peptide bonds, cupric ions react with peptide bonds to produce a violet color that is measured at 540 nm
Dry binding technique
most protein will bind with various dyes to produce colored complexes, downside is that different proteins have different affinities for different dyes resulting in variable results
Albumin determination
measured by Brom Cresol Green (BCG) and Brom Cresol Purple (BCP)
Refractometer
protein (and other substances) in solution refract light rays as they pass through the solution
