180 likes | 555 Views
MLAB 2401: Clinical Chemistry Keri Brophy -Martinez. Overview: Amino Acids & Proteins. Amino Acids. Building blocks of proteins Chemical properties determine biological activity Origin Majority made in the human Generated from amino acid pool Generated from breakdown of proteins
E N D
MLAB 2401: Clinical ChemistryKeri Brophy-Martinez Overview: Amino Acids & Proteins
Amino Acids • Building blocks of proteins • Chemical properties determine biological activity • Origin • Majority made in the human • Generated from amino acid pool • Generated from breakdown of proteins • Essential Amino acids • Ingested in diet • “MILL PATH TV”
Amino Acids • Linked together by peptide bonds to form the building blocks of proteins Peptide bond
Aminoacidopathies • Rare inherited disorders • Enzyme defect that inhibits the body’s ability to metabolize certain amino acids • Abnormality due to problem with enzyme activity or the membrane transport system for amino acids • Cause severe medical problems due to the buildup of toxic amino acids and/or byproducts of amino acid metabolism in blood
Aminoacidopathies: Disorders • Phenylketonuria • Absence of phenylalanine hydrolase • Mousy odor of the urine • Causes significant brain damage • Tyrosinemia • Three types • Type I most severe • Causes liver and kidney damage, affects CNS • Alkaptonuria • Absence of homogentisateoxidase • Urine turns brownish-black upon exposure to air
Aminoacidopathies: Disorders • Maple syrup urine disease • Absence or reduction of alpha-ketoaciddecarboxylase • Hallmark feature is the odor of maple syrup or burnt sugar in the urine, breath and skin • IsovalericAcidemia • Absence of isovaleryl-CoAdehydrogenase • Distinctive odor of sweaty feet due to build up of isovaleric acid
Aminoacidopathies: Disorders • Homocystinuria • Absence of cystathionine-beta-synthetase • Cystinuria • Defect in amino acid transport system • Results in the formation of stones
Proteins • Built from one or more chains of amino acids • Specific • Contain carbon, hydrogen, oxygen, sulfur and nitrogen • Nucleotide sequence in the genes dictates the amino acid sequence of the protein
Proteins • Synthesis • Plasma proteins made in liver then secreted by hepatocyte into circulation • Immunoglobulins made in plasma cells • Insufficient dietary quantities of amino acids will limit synthesis and lower body levels of proteins
Proteins • Catabolism (Breakdown) • Goal is to remove nitrogen from the system • Occurs in the digestive tract, kidneys, and liver • Produces ammonia, then urea • Urea excreted via urine • Produces ketoacids • Ketoacids converted to glucose or fat
Denaturation • Disruption of structure • Results in loss of function and protein chemical properties • Caused by: • Heat • pH changes • Mechanical forces • Exposure to UV light • Exposure to chemicals
Classification of Proteins • Simple proteins • Proteins made of only amino acids • Further classified as globular or fibrous • Conjugated proteins • Proteins with nonprotein groups attached • Metalloproteins • Lipoproteins • Glycoproteins • Mucoproteins • Nucleoproteins • Phosphoproteins
References • Bishop, M., Fody, E., & Schoeff, l. (2010). Clinical Chemistry: Techniques, principles, Correlations. Baltimore: Wolters Kluwer Lippincott Williams & Wilkins. • http://www.stanford.edu/group/pandegroup/folding/education/prstruc.html • Sunheimer, R., & Graves, L. (2010). Clinical Laboratory Chemistry. Upper Saddle River: Pearson .