• Journal of Life Science
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• v.28 no.12
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• pp.1545-1553
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• 2018

The International Society of Rare Sugars (ISRS) defines rare sugars as monosaccharides and their derivatives that rarely occur in nature. Rare sugars have recently received much attention because of their many uses including low-calorie sweeteners, bulking agents, and antioxidants, and their various applications including as immunosuppressants in allogeneic rat liver transplantation, as potential inhibitors of various glycosidases and microbial growth, in ischemia-reperfusion injury repair in the rat liver, and in segmented neutrophil production without detrimental clinical effects. Because they rarely exist in nature, the production of rare sugars has been regarded as one of the most important research areas and, generally, they are produced by chemical synthesis. However, the production of rare sugars by bioconversion using enzymes from microorganisms has been receiving increased attention as an environmentally friendly alternative production method. In particular, D-allulose, D-allose, and D-tagatose are of interest as low-calorie sweeteners in various industries. To date, D-tagatose 3-epimerase, D-psicose 3-epimerase, and D-allulose 3-epimerase have been reported as D-allulose bioconversion enzymes, and L-rhamnose isomerase, Galactose 6-phosphate isomerase, and Ribose 5-phosphate isomerase have been identified as D-allose production enzymes. Elsewhere, D-tagatose has been produced by L-arabinose isomerase from various microorganisms. In this study, we report the production of D-allulose, D-allose, and D-tagatose by microorganism enzymes.

• Journal of Oral Medicine and Pain
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• v.30 no.1
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• pp.15-23
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• 2005

Mucin glycoproteins are the primary carriers of the oligosaccharide moieties that constitute the blood group substances in human saliva. The aim of this study was to determine whether or not the conversion of either the A or B blood group antigens to the H antigen can occur during the degradation process of stored saliva samples. Forty subjects (20 subjects in each A and B blood group) identified as secretors were enrolled in this study. Fresh whole saliva samples and their clarified supernatants were stored at room temperature for 1 week. The conversion of the blood group antigens was detected by SDS-PAGE and immunoblotting. Among the subjects showing the conversion in whole saliva, glandular saliva samples were obtained from 8 subjects (4 subjects in each A and B blood group). Submandibular-sublingual saliva (SMSL) and a mixture of SMSL and parotid saliva (PS) were stored at room temperature for 1 week. The conversion of the blood group antigens was detected by the same method. The obtained results were as follows: 1. In the clarified samples of whole saliva, the A antigen was detected as being either intact (5%) or degraded molecules (95%) after the 1 week period. Conversion of the A antigen to the H antigen was detected in 5 subjects (25%). In the unclarified samples, the A antigen was either detected as degraded molecules (90%) or was not detected (10%). Conversion of the antigen had occurred in 4 subjects (20%). 2. In the clarified samples of whole saliva, the B antigen was detected as intact (20%) or as degraded molecules (65%) or was not detected (15%) after the 1 week period. Conversion of the B antigen to the H antigen was detected in 7 subjects (35%). In the unclarified samples, the B antigen was detected as intact (5%) or as degraded molecules (65%), or was not detected (30%). Conversion of the antigen was observed in 2 subjects (10%). 3. In the glandular saliva samples, only one of the four subjects displayed an antigenic conversion from the A to H antigen or from the B to H antigen. The conversion had occurred in both the SMSL samples and the SMSL and PS mixture. No degradation of the antigens was detected in the other three samples of the A or B blood groups, nor was there any conversion. The results demonstrated that conversion of the blood group antigens could occur in saliva, and suggested that the enzymes responsible for the conversion are present in saliva. Further studies on the origin and activity of the specific glycosidases in saliva as well as quantitative measurements of the antigenic conversion will be needed.