• Journal of Microbiology and Biotechnology
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• v.10 no.5
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• pp.573-579
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• 2000

Knowledge on the enzymes acting on p-amino-acid-containing peptides appears to be somewhat limited when compared with those acting on peptides composed on L-amino acids. Less than ten D-stereospecific enzymes are hitherto known. This review describes about several novel D-stereospecific peptidases and amidases of microbial origin, including D-aminopeptidase (E.C. 3.4.11.19), alkaline D-peptidase, and D-amino aicd amidase, which are applied to the synthesis of D-amino acid/or D-amino acid derivatives.

• Journal of Microbiology and Biotechnology
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• v.11 no.1
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• pp.29-34
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• 2001

The mutant enzymes of N-carbamyl-D-amino aicd amidohydrolase (N-carbamylase) from Agrobacterium radiobacter NRRL B11291, showing a negligible activity, were selected from the library generated by random mutagenesis. From the sequence analysis, these mutants were found to contain the amino acids substitutions at Cys172, Glu47, and Glu146. Previously, Cys172 was reported to be necessary for the enzyme catalysis. The chemical modification of the N-carbamylase by carboxyl group specific chemical reagent, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide(EDC), resulted in a loss of activity. The replacement of glutamic acids with glutamines by site-directed mutagenesis led to aggregation of the enzymes. Mutant enzymes fused with maltose binding protein (MBP) were expressed in soluble form, but were inactive. These results indicate that two glutamic acid residues play an important role in structure and function of the N-carbamylase. Multiple sequence alignment of the related enzymes revealed that Glu47 and Glu146 are rigidly conserved, which suggests that tese residues are crucial for the structure and function of the functionally related C-N hydrolases.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.9
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• pp.1162-1167
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• 2008

This study was to investigate the chemical compositions of germinated (GSS)- and ungerminated (UGSS)-safflower (Carthamus tinctorius) seeds. GSS had higher amount of sugar and crude fiber than UGSS, but less amounts of protein and lipid. Levels of $\alpha$-tocopherol and essential amino acids of GSS were higher than those of UGSS, although there are no difference in fatty acid composition between GSS and UGSS. Among the nine phenolic compounds detected, five phenolic compounds, except for two lignans and two flavonoids, were found in both GSS and UGSS. Four serotonin derivatives accounted for about 80 per cent of total phenolic compounds, and levels of five phenolic compounds decreased slightly with germination. These results suggest that germination may enhance the functionality of safflower seed by increasing nutritional compositions and by decreasing phenolic compounds with bitter taste and cathartic effects.