| 1. |
- BJöRCK, INGER M., et al.
(författare)
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In vitro Effects of Phytic Acid and Polyphenols on Starch Digestion and Fiber Degradation
- 1987
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Ingår i: Journal of Food Science. - : Wiley. - 0022-1147 .- 1750-3841. ; 52:6, s. 1588-1594
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Tidskriftsartikel (refereegranskat)abstract
- The effect of phytic acid and polyphenols on the rate and extent of starch digestion as well as on fiber degradation was studied in vitro. Addition of phytic acid only had negligible influence on the enzyme activity of the amylases tested. In contrast, enzymes concerned with starch hydrolysis in the digestive channel (α‐amylase, amyloglucosidase/maltase) were inhibited by tannic acid, and to some extent also by catechin. Furthermore, tannic acid reduced the total recovery of starch during enzymic starch analysis. The activity of cellulases and hemicellulases was not affected by phytic acid or catechin. However, the degradation of cellulose powder was inhibited by tannic acid, whereas no inhibition could be observed with carboxymethyl‐cellulose as substrate.
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| 2. |
- Nardella, F A, et al.
(författare)
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Fc epitopes for human rheumatoid factors and the relationships of rheumatoid factors to the Fc binding proteins of microorganisms
- 1988
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Ingår i: Scandinavian Journal of Rheumatology. Supplement. - : Informa UK Limited. - 1502-7740 .- 0300-9742 .- 1502-7732. ; 17:Suppl. 75, s. 190-198
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Tidskriftsartikel (refereegranskat)abstract
- Work from our laboratories has shown that the major antigenic determinants for rheumatoid factors (RFs) are in the C gamma 2-C gamma 3 interface region of IgG in the same area that binds staphylococcal protein A (SPA). Furthermore, the Fc binding proteins of groups A, C and G streptococci as well as the Fc binding proteins induced on cell surfaces by herpes simplex virus type I also bind to the same area of IgG. These binding site similarities between RFs and the microbial Fc binding proteins suggested conformational similarities between the RF antigen combining regions and the Fc binding regions of the microbial proteins. This hypothesis was supported by the observation that antibodies to SPA bind to the antigen combining regions of most RFs as well as to the Fc binding region of the T15 group A streptococcal Fc binding protein. These findings indicate that RFs bear the conformational internal image of these microbial proteins and suggest that RFs could arise as antibodies to the idiotypic determinants on antibodies to microbial Fc binding proteins. Alternatively, microbial Fc binding proteins could present IgG to the immune system in a way that renders specific areas of the C gamma 2-C gamma 3 interface region immunogenic. These relationships between RFs and microbial Fc binding proteins may prove to be important for our understanding of the generation of RFs in rheumatoid arthritis.
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| 3. |
- NYMAN, MARGARETA E., et al.
(författare)
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In Vivo Effects of Phytic Acid and Polyphenols on the Bioavailability of Polysaccharides and Other Nutrients
- 1989
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Ingår i: Journal of Food Science. - : Wiley. - 0022-1147 .- 1750-3841. ; 54:5, s. 1332-1335
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Tidskriftsartikel (refereegranskat)abstract
- The effects of the antinutrients tannic acid, catechin and phytic acid on digestion of starch, protein and lipids, and fiber degradation were studied in rat balance experiments. To separate digestion in the small intestine from fermentation in the hind‐gut, diets were tested without and with the addition of antibiotics. The antinutrients had no effects, either on starch digestion or on fiber fermentation. In contrast, inhibition of protein digestibility was observed with all antinutrients tested, while the digestibility of lipids was reduced only with phytic acid and tannic acid. The fermentability of undigestible protein was affected by tannic acid, whereas that of lipids was affected also by phytic acid.
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| 4. |
- Sjöbring, U, et al.
(författare)
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Isolation and characterization of a 14-kDa albumin-binding fragment of streptococcal protein G
- 1988
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Ingår i: Journal of immunology. - 0022-1767. ; 140:5, s. 9-1595
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Tidskriftsartikel (refereegranskat)abstract
- Protein G, a streptococcal cell wall protein, has separate binding sites for human albumin and IgG. Streptococci expressing protein G were treated with the bacteriolytic agent mutanolysin. Several IgG- and human serum albumin (HSA)-binding peptides were identified in the material thus solubilized and one of these, a 14-kDa peptide, was found to bind HSA but not IgG in Western blot experiments. This molecule was purified by affinity chromatography on Sepharose coupled with HSA followed by gel filtration on Sepharose 6B and a final affinity chromatography on IgG-Sepharose, by which low Mr W(15 to 20 kDa)IgG-binding peptides were removed. In different binding experiments the purified 14-kDa peptide bound exclusively HSA and the equilibrium constant between the peptide and HSA was determined to be 3.4 X 10(8) M-1. The relation between the 14-kDa molecule and protein G was studied by analyzing the N-terminal amino acid sequence of the peptide and comparing it with the previously determined protein G sequence. The 40 N-terminal amino acids were found to be identical with an amino acid sequence starting at position 62 in the protein G molecule. These and previous data enabled us to locate the albumin binding to the repetitively arranged domains in the N-terminal half of the protein G molecule.
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| 5. |
- Åkerström, B, et al.
(författare)
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Definition of IgG- and albumin-binding regions of streptococcal protein G
- 1987
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Ingår i: Journal of Biological Chemistry. - 0021-9258. ; 262:28, s. 91-13388
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Tidskriftsartikel (refereegranskat)abstract
- Protein G, the immunoglobin G-binding surface protein of group C and G streptococci, also binds serum albumin. The albumin-binding site on protein G is distinct from the immunoglobulin G-binding site. By mild acid hydrolysis of the papain-liberated protein G fragment (35 kDa), a 28-kDa fragment was produced which retained full immunoglobulin G-binding activity (determined by Scatchard plotting) but had lost all albumin-binding capacity. A protein G (65 kDa), isolated after cloning and expression of the protein G gene in Escherichia coli, had comparable affinity to immunoglobulin G (5-10 X 10(10)M-1), but much higher affinity to albumin than the 35- and 28-kDa protein G fragments (31, 2.6, and 0 X 10(9)M-1, respectively). The amino-terminal amino acid sequences of the 65-, 35-, and 28-kDa fragments allowed us to exactly locate the three fragments in an overall sequence map of protein G, based on the partial gene sequences published by Guss et al. (Guss, B., Eliasson, M., Olsson, A., Uhlen, M., Frej, A.-K., Jörnvall, H., Flock, J.-I., and Lindberg, M. (1986) EMBO J. 5, 1567-1575) and Fahnestock et al. (Fahnestock, S. R., Alexander, P., Nagle, J., and Filpula, D. (1986) J. Bacteriol. 167, 870-880). In this map could then be deduced the location of three homologous albumin-binding regions and three homologous immunoglobulin G-binding regions.
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