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Biomedical subjects

F G Oppenheim

Publications and source records attributed to F G Oppenheim.

At least 37 records · Page 2Linked to original sources
PubMed2001

Anticandida activity is retained in P-113, a 12-amino-acid fragment of histatin 5.

Through the analysis of a series of 25 peptides composed of various portions of the histatin 5 sequence, we have identified P-113, a 12-amino-acid fragment of histatin 5, as the smallest fragment that retains anticandidal activity comparable to that of the parent compound. Amidation of the P-113 C terminus increased the anticandidal activity of P-113 approximately twofold. The three histidine residues could be exchanged for three hydrophobic residues, with the fragment retaining anticandidal activity. However, the change of two or more of the five basic (lysine and arginine) residues to uncharged residues resulted in a substantial loss of anticandidal activity. A synthetic D-amino-acid analogue, P-113D, was as active against Candida albicans as the L-amino-acid form. In vitro MIC tests in low-ionic-strength medium showed that P-113 has potent activity against Candida albicans, Candida glabrata, Candida parapsilosis, and Candida tropicalis. These results identify P-113 as a potential antimicrobial agent in the treatment of oral candidiasis.

Amino Acid Sequence↗
PubMed2001

Salivary histatin 5 is an inhibitor of both host and bacterial enzymes implicated in periodontal disease.

One of the salient features of periodontitis and gingivitis is the increase in the levels of bacterial and host-derived proteolytic enzymes in oral inflammatory exudates. This study evaluated the potential of histatin 5, a 24-residue histidine-rich salivary antimicrobial protein, to inhibit these enzymes. Using biotinylated gelatin as a substrate, histatin 5 was found to inhibit the activity of the host matrix metalloproteinases MMP-2 and MMP-9 with 50% inhibitory concentrations (IC50s) of 0.57 and 0.25 microM, respectively. To localize the domain responsible for this inhibition, three peptides containing different regions of histatin 5 were synthesized and tested as inhibitors of MMP-9. Peptides comprising residues 1 to 14 and residues 4 to 15 of histatin 5 showed much lower inhibitory activities (IC50, 21.4 and 20.5 microM, respectively), while a peptide comprising residues 9 to 22 showed identical activity to histatin 5 against MMP-9. These results point to a functional domain localized in the C-terminal part of histatin 5. To evaluate the effect of histatin 5 on bacterial proteases, a detailed characterization of histatin 5 inhibition of gingipains from Porphyromonas gingivalis was carried out using purified Arg- and Lys-specific enzymes. Kinetic analysis of the inhibition of the Arg-gingipain revealed that histatin 5 is a competitive inhibitor, affecting only the Km with a K(i) of 15 microM. In contrast, inhibition of Lys-gingipain affected both the Km and Vmax, suggesting that both competitive and noncompetitive competitive processes underlie this inhibition. The inhibitory activity of histatin 5 against host and bacterial proteases at physiological concentrations points to a new potential biological function of histatin in the oral cavity.

Adhesins, Bacterial↗
PubMed2001

New in vitro model for the acquired enamel pellicle: pellicles formed from whole saliva show inter-subject consistency in protein composition and proteolytic fragmentation patterns.

The present investigation was undertaken to investigate the variability of proteins in whole saliva which adsorb to hydroxyapatite and are thus likely to be precursors of the acquired enamel pellicle. Whole-saliva proteins from 18 subjects were absorbed to hydroxyapatite, and the gel filtration patterns of released proteins revealed four major peaks and three minor peaks eluting between the major peaks. Amino acid analysis indicated that minor peaks contained fragments of proteins in major peaks, and this was confirmed by sequence analysis. Major peaks comprised 95% and minor peaks comprised 5% of protein absorbed to hydroxyapatite, suggesting a limited proteolytic capacity of whole saliva. HPLC elution patterns of components in minor peaks suggested that proteolysis is not totally random but is an orderly and consistent process. These studies suggest that whole saliva may be suitable as a model system for the investigation of post-secretory modifications of salivary proteins important for the formation of the acquired enamel pellicle.

Adult↗
PubMed2001

The effects of duration and intensity of stimulation on total protein and mucin concentrations in resting and stimulated whole saliva.

The present investigation has characterized the influence of the duration and intensity of stimulation on the secretion pattern of total protein and salivary mucins MG1 and MG2 in whole saliva. Resting and stimulated whole saliva was collected from six healthy subjects on 2 consecutive days. Whole saliva was collected for 2 five-minute intervals under resting conditions followed by collection under masticatory stimulation induced by the chewing of parafilm (1 g) at 10 or 60 strokes/min for 15 min. Flow rates were different under the 2 levels of stimulation. The concentration of total protein was different in resting and stimulated whole saliva but was not affected by the duration or intensity of stimulation. Analysis of mucin concentrations determined by capture ELISAs revealed that the pattern of MG1 secretion was similar to that of total protein. The pattern of MG2 secretion was unique in that no differences were observed in the concentration of this mucin under resting and stimulated conditions. This study shows that the pattern of protein secretion in whole saliva does not reflect the combined pattern observed for protein secretion in parotid and submandibular/sublingual glands, and that the secretion patterns of MG1 and MG2 in whole saliva are quite different from one another.

Adult↗
PubMed2001

Parotid salivary basic proline-rich proteins inhibit HIV-I infectivity.

OBJECTIVE: The objective of this study was to investigate the molecular nature, spectrum of activity and mechanism(s) of action of those human parotid basic proline-rich proteins that exhibit anti-HIV-I activity. DESIGN: Fractions containing the basic proline-rich proteins were obtained from human parotid saliva of presumed HIV-I non-infected human subjects and characterized with respect to their purity, apparent molecular size and their ability to inhibit the infectivity of T-tropic and M-tropic strains of HIV-I. SUBJECTS, MATERIALS AND METHODS: Stimulated parotid saliva samples were collected from human subjects who denied having any risk factors for HIV-I infection and whose parotid salivas inhibited HIV-I infectivity. Such samples were subjected to affinity, molecular sieve and ion exchange chromatography to isolate individual salivary components. Those fractions demonstrating anti-HIV-I activity were analyzed by SDS-PAGE in order to assess their purity and determine their apparent molecular weights. HIV-I inhibitory activity was determined using HIV-I strains LAI and BaL in a Hela cell-derived multinuclear activation of a galactosidase indicator (MAGI) assay. Amino acid analyses were performed on some fractions. RESULTS: Recombinant gp120-CH-Sepharose chromatography of one subject's parotid saliva revealed specific binding of human parotid basic proline-rich proteins, most prominently one with an apparent molecular weight of 37 kDa. Molecular sieve and cation exchange chromatography yielded a fraction greatly enriched in this protein which amino acid analysis confirmed was proline-rich. A similar fraction from two other subjects also contained basic proline-rich proteins of similar molecular size. These fractions inhibited both T-tropic and M-tropic strains of HIV-I when assayed in the MAGI system. Since SLPI activity is not observable in the MAGI assay, this inhibition was not due to SLPI. The presence of thrombospondin-I (TSP-I) in the active fractions was precluded on the basis of SDS-PAGE examination. CONCLUSIONS: Specific basic proline-rich proteins in human parotid saliva possess significant anti-HIV-I activity independent of that attributable to SLPI or TSP-I. Since the inhibition is detectable with the MAGI assay, its mechanism of action involves virus-host cell interaction prior to the introduction of the tat gene product into the host cell and may be through the binding of the basic proline-rich proteins to the HIV-I gp120 coat of the virus.

Amino Acids↗
PubMed2001

Physical and chemical aspects of saliva as indicators of risk for dental caries in humans.

The etiology and pathogenesis of dental caries are known to be multifactorial, but the interplay between intrinsic and extrinsic factors is still not fully understood. As in other host/parasite interactions, there appear to be marked variations in individual susceptibility to the disease. It therefore is likely that intrinsic host factors play a key role in modulating the initiation and progression of caries. The objective of this systematic review was to evaluate critically the evidence supporting the role and effects of saliva in caries pathogenesis. The full-length evidence report, including evidence tables, and the structured abstract presented at the NIH/NIDCR Consensus Development Conference on the Diagnosis and Management of Dental Caries Throughout Life, March 26-28. 2001, can be accessed at the web site http://www.nidcr.nih.gov. The present abridged report is a summary of the main findings from our evidence-based review.

Databases, Bibliographic↗
PubMed2000

Characterization of histatin 5 with respect to amphipathicity, hydrophobicity, and effects on cell and mitochondrial membrane integrity excludes a candidacidal mechanism of pore formation.

Histatin 5 is a 24-residue peptide from human saliva with antifungal properties. We recently demonstrated that histatin 5 translocates across the yeast membrane and targets to the mitochondria, suggesting an unusual antifungal mechanism (Helmerhorst, E. J., Breeuwer, P., van't Hof, W., Walgreen-Weterings, E., Oomen, L. C. J. M., Veerman, E. C. I., Nieuw Amerongen, A. V., and Abee, T. (1999) J. Biol. Chem. 274, 7286-7291). The present study used specifically designed synthetic analogs of histatin 5 to elucidate the role of peptide amphipathicity, hydrophobicity, and the propensity to adopt alpha-helical structures in relation to membrane permeabilization and fungicidal activity. Studies included circular dichroism measurements, evaluation of the effects on the cytoplasmic transmembrane potential and on the respiration of isolated mitochondria, and analysis of the peptide hydrophobicity/amphipathicity relationship (Eisenberg, D. (1984) Annu. Rev. Biochem. 53, 595-623). The 14-residue synthetic peptides used were dh-5, comprising the functional domain of histatin 5, and dhvar1 and dhvar4, both designed to maximize amphipathic characteristics. The results obtained show that the amphipathic analogs exhibited a high fungicidal activity, a high propensity to form an alpha-helix, dissipated the cytoplasmic transmembrane potential, and uncoupled the respiration of isolated mitochondria, similar to the pore-forming peptide PGLa (Peptide with N-terminal Glycine and C-terminal Leucine-amide). In contrast, histatin 5 and dh-5 showed fewer or none of these features. The difference in these functional characteristics between histatin 5 and dh-5 on the one hand and dhvar1, dhvar4, and PGLa on the other hand correlated well with their predicted affinity for membranes based on hydrophobicity/amphipathicity analysis. These data indicate that the salivary protein histatin 5 exerts its antifungal function through a mechanism other than pore formation.

Amino Acid Sequence↗
PubMed2000

The recombinant N-terminal region of human salivary mucin MG2 (MUC7) contains a binding domain for oral Streptococci and exhibits candidacidal activity.

MG2 (the MUC7 gene product) is a low-molecular-mass mucin found in human submandibular/sublingual secretions. This mucin is believed to agglutinate a variety of microbes and thus is considered an important component of the non-immune host defence system in the oral cavity. We have shown that MUC7 can bind to cariogenic strains of Streptococcus mutans and that this binding requires a structural determinant in the N-terminal region. In the present study an expression construct, pNMuc7, encoding the N-terminal 144 amino acids of MUC7 was generated, and the recombinant protein rNMUC7 was expressed in Escherichia coli. Purified rNMUC7 was characterized and the binding of this protein to oral bacteria was investigated in an established assay. The results showed that the recombinant protein bound to S. mutans ATCC 25175 and ATCC 33402, and that alkylation of the two cysteine residues (Cys(45) and Cys(50)) resulted in the complete loss of bacterial binding. This suggests that binding of MUC7 to S. mutans occurs between the N-terminal region of the mucin molecule and the bacterial surface, and that this interaction is dependent on a cysteine-containing domain within this region of MUC7. In addition, the killing activity of rNMUC7 was compared with that of the candidacidal salivary protein histatin 5 in an established Candida albicans (ATCC 44505) blastoconidia killing assay. It was found that the LD(50) values of rNMUC7 and histatin 5 were comparable, and that the recombinant protein displayed significant killing activity at the physiological concentration range of MUC7 in whole saliva. This study is the first to show that the N-terminal region of MUC7 contains a structural determinant for bacterial binding and that this region exhibits candidacidal activity.

Antifungal Agents↗
PubMed2000

Salivary mucin: a factor in the lower prevalence of gastroesophageal reflux disease in African-Americans?

OBJECTIVES: Organic and inorganic constituents of saliva have been implicated as protective components in the esophagus, and deficiencies in one or more of these factors in different races may be an important element in the prevalence of gastroesophageal reflux disease (GERD). To determine whether there are differences in the concentration of salivary mucins between different racial groups, we measured the concentration of mucous glycoprotein MG1 and mucous glycoprotein MG2 in whole saliva of African-Americans and Caucasians. METHODS: Whole saliva was collected from 19 African-American (four male, 15 female; mean age 34 yr, range 19-53 yr) and 25 Caucasian (11 male, 14 female; mean age 31 yr, range 20-51 yr) volunteers under masticatory stimulation (1 g Parafilm, 60 strokes/min) between 11:00 AM and 12:00 noon. Total salivary carbohydrate was measured with a periodic acid-Schiff assay and total protein by absorbance at 215 nm. Immunological reagents were employed to quantify MG2 in a combined enzyme-linked immunosorbent assay/enzyme linked lectin assay (ELISA/ELLA) and to quantify MG1 in a capture ELISA. RESULTS: The total carbohydrate, protein, MG1 and MG2 values were 24.4 +/- 11.9, 243.5 +/- 62.7, 21.8 +/- 13.4, and 11.6 +/- 9.5 mg% for African-Americans, and the corresponding values were 23.3 +/- 9.3, 221.7 +/- 39.7, 25.7 +/- 16.2, and 10.9 +/- 8.7 mg% for Caucasians. There was no statistical difference for any of the parameters measured between the two groups. Furthermore, it was shown that no correlation existed between salivary flow rate and the concentration of carbohydrate, protein, or salivary mucins in African-Americans and in Caucasians. These results show that flow rate did not influence the measured values for salivary parameters in the two groups. CONCLUSIONS: No differences were found in the concentration of salivary mucins MG1 and MG2 in whole saliva of African-Americans and Caucasians, and it seems unlikely that variations in mucin levels influence the prevalence of GERD in these groups.

Adult↗
PubMed2000

Candida albicans mutants deficient in respiration are resistant to the small cationic salivary antimicrobial peptide histatin 5.

Histatins are a group of small cationic peptides in human saliva which are well known for their antibacterial and antifungal activities. In a previous study we demonstrated that histatin 5 kills both blastoconidia and germ tubes of Candida albicans in a time- and concentration-dependent manner at 37 degrees C, whereas no killing was detected at 4 degrees C. This indicated that killing activity depends on cellular energy. To test histatin 5 killing activity at lower cellular ATP levels at 37 degrees C, respiratory mutants, or so-called petite mutants, of C. albicans were prepared. These mutants are deficient in respiration due to mutations in mitochondrial DNA. Mutants were initially identified by their small colony size and were further characterized with respect to colony morphology, growth characteristics, respiratory activity, and cytochrome spectra. The killing activity of histatin 5 at the highest concentration was only 28 to 30% against respiratory mutants, whereas 98% of the wild-type cells were killed. Furthermore, histatin 5 killing activity was also tested on wild-type cells in the presence of the respiratory inhibitor sodium azide or, alternatively, the uncoupler carbonyl cyanide m-chlorophenylhydrazone. In both cases histatin 5 killing activity was significantly reduced. Additionally, supernatants and pellets of cells incubated with histatin 5 in the presence or absence of inhibitors of mitochondrial ATP synthesis were analyzed by sodium dodecyl sulfate gel electrophoresis. It was observed that wild-type cells accumulated large amounts of histatin 5, while wild-type cells treated with inhibitors or petite mutants did not accumulate significant amounts of the peptide. These data showed first that cellular accumulation of histatin 5 is necessary for killing activity and second that accumulation of histatin 5 depends on the availability of cellular energy. Therefore, mitochondrial ATP synthesis is required for effective killing activity of histatin 5.

Acriflavine↗
PubMed2000

Molecular mapping of statherin- and histatin-binding domains in human salivary mucin MG1 (MUC5B) by the yeast two-hybrid system.

MGI is a high-molecular-weight mucin secreted by mucous acinar cells in human submandibular and sublingual glands. We have recently shown that the tracheobronchial mucin MUC5B is a major component of MG1. MUC5B is organized into cysteine-rich N- and C-terminal regions that flank a central tandem-repeat region containing cysteine-rich subdomains and imperfect 29-residue tandem repeats. In earlier work, we have shown that this mucin selectively forms heterotypic complexes with amylase, proline-rich proteins, statherin, and histatins in salivary secretions, and the aim of this study was to identify specific binding domains within MUC5B using the yeast two-hybrid system. Interactions of cysteine-rich domains in the tandem-repeat region (Cys1-Cys4) and C-terminal region (Cys8a, Cys8b, Cys8c) of MUC5B with statherin and histatins were investigated. These studies indicated that histatin 1 selectively bound to Cysl and Cys2, whereas statherin and histatin 1, 3, and 5 selectively bound to Cys8a. Analysis of the primary sequences of the identified binding domains suggests that these domains most probably can fold into globular-like structures in the native mucin. A ProDom blast search revealed that sequences in Cys1, Cys2, and Cys8a exhibit similarity to domains in evolutionarily diverse extracellular proteins known to participate in a wide variety of protein-protein interactions.

Amylases↗
PubMed2000

Pellicle precursor protein crosslinking characterization of an adduct between acidic proline-rich protein (PRP-1) and statherin generated by transglutaminase.

Recent work with oral transglutaminase indicated that this enzyme, derived from oral epithelial cells, crosslinked pellicle precursor proteins which may be important in the formation of the acquired enamel pellicle. The purpose of this study was to investigate whether purified acidic PRP-1 can form crosslinks with statherin, and whether such a crosslink is derived from a transglutaminase-catalyzed reaction between glutaminyl and lysyl side-chains, leading to a covalent bond formation. Enzymatic reaction products were analyzed by SDS-PAGE and reverse-phase HPLC. The SDS electrophoretogram revealed a protein band with an apparent molecular weight of 32 kDa, which is consistent with the combined apparent molecular weight of acidic PRP-1 (24 kDa) and statherin (8 kDa). A reaction product isolated by HPLC was characterized by amino acid analysis, which showed a stoichiometry consistent with being an adduct composed of one molecule of acidic PRP-1 and one molecule of statherin. In negative control experiments, it could be shown that this adduct was not detected when the lysines of both substrates were modified by reductive methylation prior to the enzymatic reaction. In addition, amino acid analysis and mass spectrometry confirmed the presence of a gamma-glutamyl-epsilon-lysine dipeptide after enzymatic hydrolysis and the absence of this dipeptide after acid hydrolysis. Analysis of the data obtained indicates that oral transglutaminase is capable of crosslinking acidic PRP-1 and statherin in vitro. In addition, this finding exemplifies the potential of post-secretory processing of salivary proteins, which may represent an additional mechanism to generate new protein species.

Amino Acids↗
PubMed2000

Immunoquantification of human salivary mucins MG1 and MG2 in stimulated whole saliva: factors influencing mucin levels.

While more and more is known about the structure and function of human salivary mucins, there is relatively little information on quantification of these glycoconjugates in whole saliva and on factors influencing their secretion. The goal of the present work was to develop capture ELISAs that would allow for rapid, inexpensive, and reliable measurement of the salivary mucins MG1 and MG2, and to use these immunological procedures to investigate the significance of age, gender, flow rate, and protein concentration on mucin levels in whole saliva. Previously, we described a rabbit polyclonal antibody against MG1 (Troxler et al., 1995) and a rabbit polyclonal peptide antibody against an epitope in the N-terminal region of MG2 (Liu et al., 1999) which were used to develop the capture ELISAs. We verified the accuracy and specificity of these assays by showing correct measurement of known quantities of purified MG1 or MG2 added to whole saliva and lack of cross-reactivity between mucins and heterologous antisera on Western blots or in ELISAs. Whole saliva was collected from 60 subjects under conditions of masticatory stimulation, flow rates were recorded, and mucin concentrations were determined. The results showed that the mean concentration of MG1 and MG2 was 23.3 +/- 14.6 mg% and 13.3 +/- 11.6 mg%, respectively, and that mucins constitute approximately 16% of the total protein in whole saliva. No significant correlations were found between mucin levels and age or flow rate; however, a significant correlation was found between MG2 levels and total protein concentration. Furthermore, there were statistically significant gender differences in flow rate and MG1 levels, but not in MG2 levels. The availability of these immunoassays for quantification of MG1 and MG2 will help to elucidate the role of mucin in oral health and disease.

Adult↗
PubMed1999

Isolation of human salivary mucin MG2 by a novel method and characterization of its interactions with oral bacteria.

Human salivary mucin MG2 was purified from submandibular/sublingual gland secretion by ultrafiltration and sequential gel filtration chromatography on Sephadex G-200, Superose 6 (prepgrade), and Superose 6. This method differs from earlier procedures in that all steps are performed in the presence of 4 M guanidine hydrochloride and do not involve covalent modification of the mucin molecule. Electrophoretic analyses and Western blotting showed that purified MG2 did not contain detectable levels of other salivary proteins. Amino acid analysis showed that the composition of purified MG2 was in excellent agreement with the deduced sequence of MG2 apomucin encoded in the MUC7 gene. The yield of purified MG2 was 10-15 mg from 750 ml of salivary secretion. Binding of purified MG2 to Streptococcus mutans in vitro was not significantly affected by reductive methylation, but was nearly abolished by reduction and alkylation. These data identified a functional determinant for mucin-bacterial interactions in the N-terminal region where the only two cysteines (Cys45 and Cys50) in the MG2 apomucin occur. Additionally, purified MG2 bound to four strains of oral Streptococci, indicating that the binding is not dependent on complexing with other salivary proteins, such as secretory immunoglobulin A. The purification procedure described in this work will facilitate investigation of the role of MG2 in the oral environment.

Adult↗
PubMed1999

Salivary histatins in patients with recurrent oral candidiasis.

The level of salivary histatins was evaluated in 20 patients with a history of recurrent oral candidiasis and in age-, sex-matched healthy controls. Salivary pH, flow rate, total protein and histatins were compared. Results of this study indicated that salivary pH was significantly lower among patients than controls (5.9 vs. 6.3, respectively, P = 0.002). No significant difference was observed in the mean flow rate and total protein between patients and controls (0.39 ml/min/gland vs. 0.46 ml/min/gland and 112.4 mg% vs. 113.0 mg%, respectively). However, the mean salivary histatin levels were significantly higher among patients than controls, both in terms of concentration (16.8 mg% vs. 11.1 mg%, P = 0.016) as well as a ratio of total protein (15 mg/g vs. 10 mg/g, P = 0.018). These findings indicate that oral candidiasis is associated with increased levels of salivary histatin. Such a finding suggests that oral candidiasis may modulate the levels of salivary histatin.

Acute-Phase Proteins↗
PubMed1999

Pellicle precursor proteins: acidic proline-rich proteins, statherin, and histatins, and their crosslinking reaction by oral transglutaminase.

Previous studies have demonstrated that whole saliva and pellicle formed in vitro from oral fluid contain covalently crosslinked salivary proteins. The purpose of this study was to determine which salivary proteins can act as substrates for transglutaminase, an enzyme responsible for the covalent crosslink reaction between a glutamine residue and a lysine residue. Transglutaminase was prepared from the pellet fraction of human whole saliva. Dansyl cadaverine (N-dansyl-1,5-diaminopentane) was used to study the reactivity of glutamine residues in acidic large and small proline-rich proteins, statherin, and the major histatins, whereas a glutamine-containing dansylated peptide was used to study the reactivity of lysine residues in these proteins. Crosslink formation was measured fluorometrically after the addition of fluorescent probe to the salivary protein substrate and transglutaminase. The covalent attachment of the fluorescent probe to salivary proteins was confirmed by SDS-PAGE. It was found that almost all of the lysines present in the acidic PRPs and statherin, and some of the lysines present in histatins, could participate in the crosslink reaction. Glutamine reactivity was also observed, but a maximum of only 14% of glutamine residues present in acidic PRPs and statherin participated in the crosslink formation. These results demonstrate that primary pellicle precursor proteins, acidic proline-rich proteins, statherin, and the major histatins are capable of undergoing crosslink reactions catalyzed by oral transglutaminase. This may enable other proteins in the oral cavity to be incorporated into the acquired enamel pellicle.

Amino Acids↗
PubMed1998

MUC4 is a major component of salivary mucin MG1 secreted by the human submandibular gland.

High molecular weight salivary mucin (MG1) is an important component of saliva, contributing to the lubricative and tissue-protective functions of this biological fluid. We have shown previously that the human mucin gene MUC5B is expressed at high levels in sublingual gland and is a significant constituent of MG1. Since many epithelia express multiple mucin genes, it seemed likely that MG1 in salivary secretions is also a heterogeneous mixture of mucin gene products. The aim of this study was to determine whether MUC4, a mucin shown in Northern blotting experiments to be expressed in salivary glands, was a significant protein component of MG1 in salivary secretions. Two cDNA clones containing MUC4 tandem repeats were isolated from a human submandibular gland cDNA library. In addition, recombinant MUC4 produced in a bacterial expression system cross-reacted with an antibody directed against deglycosylated MG1. This shows conclusively that human salivary mucin MG1 contains both MUC5B and MUC4 gene products suggesting that each mucin may perform distinct functions in the oral cavity.

Amino Acid Sequence↗