Lesson 5: Amino Acids, Peptides, Proteins (Peptides, Proteins)

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Peptides
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Terms in this set (68)
Peptides
Polymers of several amino acids joined by peptide bonds
Protein
Any large compound made from one or more polypeptides joined by peptide linkages between amino group of one and the carboxylic acid group of the next
Primary, Secondary, Tertiary, Quaternary
Elements of Proteins
Primary Structure
(Element) Refers to the sequence of amino acids in a peptide or protein
Secondary Structure
(Element) Involves winding of the polypeptide chain
Secondary Structure
(Element) Refers to the specific 3-dimensional conformations (alpha, helix, beta pleated and random structure)
Tertiary Structure
(Element) Actual 3-dimensional configuration
Tertiary Structure
(Element) The folding of the polypeptide chains and elements of the secondary structure into a compact 3-dimensional shape
Tertiary Structure
(Element) Responsible for the physical and chemical properties of the protein
Quaternary Structure
(Element) Incorporation of two or more polypeptide chains or subunits into a larger unit
Simple, ConjugatedClassification of Protein (2)Simple Protein(Classification) Contains peptide chains which on hydrolysis yield only amino acidsFibrous, Globular 2 Types of Simple ProteinFibrinogen, Troponin, Collagen3 Examples of FibrousHemoglobin, Plasma proteins, Enzymes , Peptide hormones4 Examples of GlobularConjugated Proteins(Classification) Composed of a protein (apoprotein) and a nonprotein compound (prosthetic group)Metalloproteins, Lipoprotein, Glycoproteins, Mucoproteins, Nucleoproteins5 Types of conjugated proteinFerritin, ceruloplasmin, hemoglobin, flavoproteins4 Examples of MetalloproteinsHDL, LDL, VLDL3 Examples of LipoproteinsHaptoglobin, alpha-1-antitrypsin2 Examples of GlycoproteinsmucinExample of MucoproteinsChromatinExample of Nucleoproteins220nm-280nmPeak absorbance of the protein16%Content of nitrogen present in proteinCan bear both positive and negative chargeProtein is amphoteric which means?4%What percentage is decreased in the total protein content of serum during coagulation?SerumPreferred specimen for protein electrophoresis - fibrinogen yields a prominent band in the beta-gamma borderPlasmaIt has all the coagulation proteins lacking in the serumPlasmaIt represents a protein and peptide composition more similar to that seen in in-vivo conditionsPlasmaIt is recommended for photometric analysisambulatory patientsTPC are higher for patients under bed rest or ambulatory patients?hemodilutionredistribution of extracellular fluid to the intravascular space results tohemoconcentrationHigh levels of protein are expected during prolonged standing this can result to?Kjeldahl Method(Analytical Method) Reference method for total protein measurementKjeldahl Method(Analytical Method) Protein nitrogen is converted to ammonium ion by heating with sulfuric acid in the presence of a catalystKjeldahl Method, Biuret Method, Direct Optimal, Dye-binding, Lowry (Felin-Ciocalteu), Refractometry, Turbidimetric & Nephelometric7 Analytical Methods For Total Proteindistillation into acid and titrationIn Kjeldahl Method, what is the recommended method for ammonium ion measurement6.25In Kjeldahl Method, Total serum protein is obtained by multiplying TPN by ______Biuret Method(Analytical Method) Most widely used and IFCC-recommended methodBiuret Method(Analytical Method) Under strongly alkaline conditions, copper ions form multivalent complexes with peptide bonds in proteins.540nmWavelength of absorbance in Biuret Methodalkaline copper sulfate, rochelle salt (NaK Tartrate), NaOH and potassium iodide3 Reagents used in Biuret Method16 g/dlBiuret method is linear up to how many g/dl of proteins?Hemoglobin, Bilirubin2 Interference in Biuret methodDirect Optical Method(Analytical Method) Proteins absorb light optimally at UV range200-225nm and 270-290nmThese are the most commonly used wavelength in Direct Optical Methodtryptophan and tyrosine In Direct Optical Method at 280nm what can be absorbed?peptide bonds In Direct Optical Method at 200-225nm what can be absorbed?Dye-Binding Methods(Analytical Method) Based on shifts in the absorbance spectra of dyes when they bind to proteinsPyrogallol redmost commonly used in Dye-Binding MethodsDye-Binding Methods(Analytical Method) Good sensitivity, may be used for fluids with lower protein concentrations such as urine and CSFLowry (Felin-Ciocalteu) MethodSpecimens are mixed with an alkaline copper solution followed by addition of Folin-Ciocalteu reagentdeep blueIn Lowry (Felin-Ciocalteu) Method, it involves the oxidation of phenolic compounds such as tyrosine, tryptophan and histidine to give what color?650-750nmIn Lowry (Felin-Ciocalteu) Method, absorbance of products are measured at?Refractometry(Analytical Method) Measurement of the light-bending capacity of solutionsRefractometry(Analytical Method) Estimation of protein concentration based on measurement of refractive index due to solutes in serumRefractometry(Analytical Method) Used to rapidly estimate protein at high concentrations<35 g/LIn Refractometry, Accuracy decreases at how many g/L?Trichloroacetic acid, Sulfosalicylic acid, SSA with Sodium sulfate, Benzethonium chloride, Benzalkonium salts under alkaline conditionsIn Turbidimetric And Nephelometric Methods, proteins are aggregated before analysis by (5)6.5-8.5 g/dlReference Range For Total Protein of Plasma6.3-8.3 g/dlReference Range For Total Protein of SerumDehydration(Disease Correlation) What can be the result of an increase protein level?Overhydration, Inflammation(Disease Correlation) What can be the result of decreased protein level?DehydrationIn increased protein levels this results to, decreased water intake, increased water loss (Diarrhea , Severe vomiting , Addison's disease , Diabetic acidosis) and causes relative increase - hemoconcentrationHemoconcentrationIncreased blood concentrationHemodilutionDecreased blood concentrationAlbuminIt is the largest fraction of serum proteinAlbuminWhat does inflammation decrease?