Salivary Proteins - Dental Biochemistry - Lecture Slides, Slides of Biochemistry

Download Salivary Proteins - Dental Biochemistry - Lecture Slides and more Slides Biochemistry in PDF only on Docsity! Salivary Proteins Docsity.com Clinical Importance  Demographic change - the number of elderly will increase  Implications: Increases in diseases affecting salivary glands Sjogren's syndrome, other autoimmune diseases, Head and neck cancer (radiation therapy) Increased use of medications with effects on saliva Anticholinergic (antihistamines, antidepressants) • Reduced flow - indirect/direct effects on proteins Beta adrenergic agonists and antagonists • Direct effects on protein synthesis/secretion • (asthma, hypertension, cardiovascular disease) Docsity.com Functions - Protect tissues  Protect oral surfaces by forming pellicle Statherin, acidic proline-rich proteins, amylase, histatins, cystatins, MUC7 mucin, lysozyme, albumin, carbonic anhydrase  Lubrication - oral surfaces must slide freely Statherin, MUC5B mucin (also reflux protection)  Maintain saliva calcium in equilibrium with enamel Saliva supersaturated with calcium and phosphate Precipitation must be prevented Statherin, aPRP, histatins, cystatins Docsity.com Functions - Food processing  Initial breakdown of starches - Amylase  Binding/detoxification of dietary tannins aPRP, basic PRP, histatins  Protein processing - Kallikrein and other proteases  Swallowing - MUC5B Docsity.com Functions - Manage Microbes  Antimicrobial functions (bacteria, fungi, viruses) Direct - cell killing - Histatins, lysozyme, amylase, MUC7, lactoferrin, defensins, peroxidase Indirect - Inhibition of infectivity, microbial metabolism, bacterial/viral proteases - Lactoferrin, cystatins, histatins, basic PRP, SLIPI, peroxidase, S-IgA "Aggregation" - bind to microbes, clear by swallowing - MUC7, lysozyme, lactoferrin, glcosylated PRP, parotid agglutinin, extra- parotid glycoprotein, S-IgA Docsity.com Fragments and Complexes  Many salivary proteins are cleaved by proteases During secretion or in the mouth aPRP, bPRP, gPRP, histatins, S-IgA Fragments may function differently than intact proteins  Proteins function differently together than they do alone Lysozyme, lactoferrin, peroxidase  Salivary proteins bind in large heterotypic complexes MUC5B, amylase, aPRP, S-IgA, peroxidase, lysozyme, lactoferrin, statherin Complexes function differently than component proteins Docsity.com Pictures of proteins in pellicle histatins aPRP statherin Docsity.com Pictures of Proteins In pellicle statherin : histatins Docsity.com Histatins up close  Multigene family - largest is phosphoprotein, others not  Small peptides after proteolysis Positive charge - histidine-rich  Microbial cell damage - antibacterial and anti-fungal Also Ca2+ balance, tannin binding, protease inhibitor  Clinical interest - very safe - easy to make Early trials with histatin rinses and gels Some benefit in experimental gingivitis model • No oral hygiene for a month No trials with caries, periodontitis, or candidiasis patients yet Docsity.com Current Products  Products with added lysozyme, lactoferrin, peroxidase  All influence aggregation/adherence, plus unique effects Px enzyme - bacterial H2O2 + saliva SCN- > OSCN- OSCN- inhibits/kills bacteria Removing H2O2 may protect soft tissues Lz enzyme cleaves bacterial cell walls > lysis Also positive charge effects similar to histatins Lf sequesters iron from some microbes, but not all Unsaturated Lf is independently bactericidal  Clinical interest - can be purified from cow's milk Biotène™ toothpaste, rinses, gum, dry mouth gels Minor to minimal benefit in published clinical trials Docsity.com Future Prospects  Ideas about salivary protein function come from lab  Experimental models are greatly simplified Change only one factor at a time  The mouth is an extremely complex environment Difficult to isolate effects of single proteins Redundancy may “dilute” the effects of supplements  We need to understand how different proteins work together Supplements may need to be in the form of protein complexes Docsity.com