The Calcium-Binding Effect of a Human Salivary Glycoprotein

Rölla, Gunnar; Jonsen, Jon

doi:10.1159/000259534

Cited by 11 publications

(4 citation statements)

References 4 publications

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“…Comprehensive studies of calcium binding by proteins present in human saliva have not been done, though some individual proteins have been investigated, particularly the anionic proline-rich proteins [23][24][25][26][27]. These proteins bind calcium [23,24] and, under salivary conditions, would be expected to bind 1-2 mol Ca2+/mol PRP.…”

Section: Discussionmentioning

confidence: 99%

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Equilibrium dialysis and ultrafiltration studies of calcium and phosphate binding by human salivary proteins. Implications for salivary supersaturation with respect to calcium phosphate salts

Hay¹,

Schluckebier²,

Moreno³

1982

Calcif Tissue Int

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Previous ultrafiltration studies indicated that up to one-half of the calcium and two-thirds of the phosphate in human salivary secretions may be bound by salivary proteins. Since this binding is an important variable in determining the extent of salivary supersaturation with respect to calcium phosphate salts, and since the amount of binding reported is surprisingly large, calcium and phosphate ion-binding by salivary macromolecules has been reexamined. From experiments using equilibrium dialysis, it was found that (1) the fraction of salivary calcium involved in macromolecular complexes ranges from a few percent for unstimulated secretions, to no more than about 10% for stimulated glandular salivas, and (2) salivary proteins do not bind phosphate ions to any significant extent. These findings, and experiments using an improved ultrafiltration membrane, indicate that the earlier results were artifacts of the ultrafiltration technique. Fractionation of salivary proteins, followed by equilibrium dialysis measurements, showed that the anionic proline-rich proteins and a basic proline-rich glycoprotein are responsible for most of the calcium binding now observed. The finding that macromolecular complexes of salivary calcium and phosphate have been overestimated in the past, leads to the conclusion that salivary calcium and phosphate ion activities in stimulated salivary secretions may be up to 50 to 100% higher than previously thought. Revised values were therefore used to recalculate the degree of salivary supersaturation with respect to calcium phosphate salts. The results indicate that stimulated salivary secretions are supersaturated with respect to dicalcium phosphate dihydrate; this is a substantially greater degree of supersaturation than previously reported.

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Section: Discussionmentioning

confidence: 99%

“…This would apply to proteins present at substantially lower concentrations than the PRP [26,27], or to proteins like amylase [29], the affinity constants of which are so high that they are fully saturated under salivary conditions, and consequently are not involved in the binding reactions of the kind studied here.…”

Section: Discussionmentioning

confidence: 99%

Equilibrium dialysis and ultrafiltration studies of calcium and phosphate binding by human salivary proteins. Implications for salivary supersaturation with respect to calcium phosphate salts

Hay¹,

Schluckebier²,

Moreno³

1982

Calcif Tissue Int

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“…Little is known about other Ca2+-binding proteins in saliva. Rolla & Jonsen (1967) isolated a glycoprotein from submandibular saliva that could bind Ca2+, and Boat et al (1974) have isolated a Ca2+-precipitable protein from submandibular saliva, which may also be present in parotid saliva. A Ca2+-precipitable protein has also been isolated from mixed salivary secretions by Belcourt (1975).…”

mentioning

confidence: 99%

The binding of calcium to a salivary phosphoprotein, protein A, common to human parotid and submandibular secretions

Bennick

1976

Biochemical Journal

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“…Certain adrenergic antagonists (phentolamine, reserpine) appear to potentiate or mimic these effects of isoproterenol (Mandel & Katz, 1968;Martinez et al, 1975a, b). Submandibular glands produce sialic acid-rich glycoproteins which bind Ca2f readily (Leung & Draus, 1962;Rolla & Jonsen, 1967), and the sialic acid content of submandibular glands is increased following isoproterenol administration (Shackleford & Klapper, 1962;Byrt & Glanvill, 1967;Curbelo et al, 1968). If calcium is responsible for intra-granule aggregation of secretory material, one would expect the saliva from male rats to possess higher Ca2+ concentrations than females.…”

Section: Discussionmentioning

confidence: 99%

Morphology and cytochemistry of acinar secretory granules in normal and isoproterenol‐treated rat submandibular glands

Simson

Dom

Sannes

et al. 1978

Journal of Microscopy

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Several fixation procedures have been utilized in a fine-structural study of rat submandibular glands with the aim of correlating the morphology of granule substructure with its composition. Procedures included fixation with aldehyde in a variety of buffers, with or without fixation additives such as tannic acid or calcium chloride. Both immersion and perfusion fixation studies were performed. Osmium tetroxide postfixed tissue was compared with non-postfixed tissue. Thin sections were stained for carbohydrate-containing constituents by either periodic acid-thiocarbohydrazide-silver proteinate or tannic acid-ferric chloride sequences. The morphology and cytochemistry of acinar secretory granules were highly dependent upon the fixation procedure utilized. In postfixed tissue, fine filaments and vesicles were the major granule constituents. Filaments often aggregated into fibrils in fixatives containing phosphate buffer or calcium, whereas vesicles were prominent with fixatives containing collidine buffer. Tannic acid, as a fixation additive, imparted enhanced density to the peripheral rim of aggregated filaments. If post fixation was eliminated, an amorphous meshlike material was the major granule component. This stained readily with methods for carbohydrate whereas the granules of post-osmicated tissue did not. Following chronic isoproterenol treatment the degree of filament aggregation in postfixed tissue was augmented, and this corresponded to an increase in amount of material stainable for carbohydrate in non-post-osmicated tissue.

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The Calcium-Binding Effect of a Human Salivary Glycoprotein

Cited by 11 publications

References 4 publications

Equilibrium dialysis and ultrafiltration studies of calcium and phosphate binding by human salivary proteins. Implications for salivary supersaturation with respect to calcium phosphate salts

Equilibrium dialysis and ultrafiltration studies of calcium and phosphate binding by human salivary proteins. Implications for salivary supersaturation with respect to calcium phosphate salts

The binding of calcium to a salivary phosphoprotein, protein A, common to human parotid and submandibular secretions

Morphology and cytochemistry of acinar secretory granules in normal and isoproterenol‐treated rat submandibular glands

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