biochemistry of saliva

Question 1

general function

Answer 1

1) salivary glands,
2) 800-1500 mL, 6-7 pH
3) acinar cells
—
1) moisten food
2) digestion
3) dental enamel maintenance
4) inhibit infection

Question 2

inorganic components

Answer 2

1) calcium and phosphate
- prevent dissolution of enamel
2) calcilum
- 1.4 mM
-50% in ionic form
3) phosphate
- 6 mM
- 90% in ionic form
4) at pH 6, hydroxyapatite is unlikely to dissolve

Question 3

hydrogen carbonate

Answer 3

1) huffer
2) low in unstimulated saliva, increases with flow rate
3) increase pH up to 8
4) defense against cariogenic bacteria
5) derived from carbonic anhydrase VI (from Co2)

Question 4

carbonic anhydrase and saliva pH

Answer 4

1) low buffering capacity = more enamel erosion
2) high salivary flow rate = more bicarbonate for buffering
3) acid introduction stimulates salivary flow

Question 5

other ions

Answer 5

1 )fluoride
- low concentration, similar to plasma
2) thiocyanate
- antimicrobial
- higher concentration = lower caries
3) sodium, potassium, etc

Question 6

mucins

Answer 6

1 )lubrication
2) glycoproteins
- oligosaccharide side chains
3) hydrophilic, absorbs water
4) high elasticity, adhesiveness, low solubility
5) two major
- MG1 and MG2
6) protect enamel against cariogenic bacteria

Question 7

amylases

Answer 7

1) calcium metalloenzyme
2) hydrolyzes starches such as amylose and amylopectin
3) several salivary isoenzymes
4) maltose is the major end product
5) contributes to digestion
- inactivated in stomach

Question 8

lingual lipase

Answer 8

1) lingual glands and parotid
2) first phase of fat digestion
3) hydrolyze triglycerides
4) it is highly hydrophobic

Question 9

statherins

Answer 9

1) calcium phosphate salts of dental enamel are soluble under typical pH and ionic strength
2) supersaturation of calcium phosphates maintains enamel
2) prevent precipitation or crystallization of supersaturated calcium phosphate in ductal saliva
4) acinar cells in salivary glands

Question 10

statherin in diabetes

Answer 10

1) low levels in diabetes
2) negatively correlated with fasting glucose levels
3) higher decayed, missing, or filled teeth

Question 11

proline rich proteins

Answer 11

1) 40% of amino acids have this
2) inhibit calcium phosphate crystal growth
- healthy levels of soluble calcium
3) part of pellicle
4) three groups
- acidic
- basic
- glycosylated

Question 12

lactoferrin

Answer 12

1) iron binding proteins
2) nutritional immunity
- starve bacteria
3) some microorganisms make siderophores
- strong Fe3+ binding agents, which is more than lactoferrin
4) lactoferrin can be degraded by some bacterial protease

Question 13

histatins

Answer 13

1) small proteins that inhibit fungal growth
2) ex. candida albicans

Question 14

cystatins

Answer 14

1) inhibit cysteine proteases
2) in many body fluids
3) protect against unwanted proteolysis
- bacterial
- and lysed leukocytes
4) inhibit proteases in periodontal tissues

Question 15

salivary peroxidase systems

Answer 15

1) catalyze oxidation of different substrates by hydrogen peroxide
2) sialoperoxidase
- acinar calls of parotid glands
- in submandibular saliva
- absorbed to various surfaces of mouth (enamel, bacteria, dental plaque)
3) myeloperoxidase
- from leukocytes entering via gingival crevice
- 15-20% of total peroxidase in whole saliva

Question 16

lysozyme

Answer 16

1) present in numerous organs and most body fluids
2) hydrolysis of bond between N-acetylmuramic acid and N-acetylglucosamine in peptidoglycan
- gram negative bacteria are more resistant than gram positive, with 2nd membrane

Question 17

secretory immunoglobulins

Answer 17

1 ) igA secreted by mucosal linings
2) secretory IgA (dimeric)
3) protects immunoglobulin from degradation by proteolysis (secretory component)
4) sticks to mucosa, produced by plasma cells in salivary glands
5) most IgG from serum and some locally produced
- more IgA in saliva tho

Question 18

just spit it our

Answer 18

1) microbes and proteins that inhabit the human mouth have diagnostic qualities
2) oral microbes and chronic disease
- CVD
- lung infection
- diabetes
- dementia / alzheimers
- obesity
- pre-term birth
- migraines?

Question 19

saliva analysis

Answer 19

1) microbiota
2) oral proteins (cytokines)
3) steroids (cortisol)
4) DNA, RNA, microRNA

Question 20

oral microbes difficult to study

Answer 20

1) anaerobic, killed of O2
- cannot culture
2) however, 16S ribosomal RNA survives
- over 600 species in mouth, 60% cannot be cultivated outside

Question 21

microbes

Answer 21

1) migraines are correlated with higher levels of nitrate
2) our cells cannot metabolize them

Question 22

protein biomarkers

Answer 22

1) oral cancer
2) risk for diabetes