An enzyme, horseradish peroxidase (HRP), was adsorbed in the manner of the single immersion method on the silica mesoporous materials FSM-16, MCM-41, and SBA-15 with various pore diameters from 27 to 92 Å, and their enzymatic activities in an organic solvent and the thermal stabilities were studied. FSM-16 and MCM-41 showed a larger amount of adsorption of HRP than SBA-15 or silica gel when the pore sizes were larger than the 50 Å. The increased enzyme adsorption capacity may be due to the surface characteristics of FSM-16 and MCM-41, which would be consistent with the observed larger adsorption capacity of cationic pigment compared with anionic pigment for these materials. The immobilized HRP on FSM-16 and MCM-41 with pore diameter 50 Å showed the highest enzymatic activity in an organic toluene and thermal stability in aqueous solution at the temperature of 70 °C. The immobilized enzymes on the other mesoporous materials including large or small pore sized FSM-16 showed lower enzymatic activity in an organic solvent and thermal stability. Both surface character and size matching between pore sizes and the molecular diameters of HRP were important in achieving high enzymatic activity in organic solvent and high thermal stability.

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;The Purple leaf (Pl) locus of rice (Oryza sativa L.) affects regulation of anthocyanin biosynthesis in various plant tissues. The tissue-specific patterns of anthocyanin pigmentation, together with the syntenic relationship, indicate that the rice Pl locus may play a role in the anthocyanin pathway similar to the maize R/B loci. We isolated two cDNAs showing significant identity to the basic helix-loophelix (bHLH) proteins found in the maize R gene family. OSB1 appeared to be allelic to the previously isolated R homologue, Ra1, but showed a striking difference at the Cterminus because of a 2-bp deletion. Characterization of the corresponding genomic region revealed that the sequence identical to a 5¢ ¢ ¢ ¢-portion of OSB2 existed~10-kb downstream of the OSB1 coding region. OSB2 lacks a conserved C-terminal domain. Restriction fragment length polymorphism analyses using an F 2 population indicate that both genes co-segregate with the purple leaf phenotype. A transient complementation assay showed that the anthocyanin pathway is inducible by OSB1 or OSB2. These results suggest that the Pl w allele may be complex and composed of at least two genes encoding bHLH proteins.

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