Recent advances in genetic engineering techniques have enabled the determination of complete amino acid sequences of cytochrome P450's. Alignment of the known sequences revealed the presence of several homologous regions in the sequence. These data together with results for the crystallographic structure suggested that highly conserved residues in the oxygen binding pocket, Asp and Thr residues play a key role in the oxygen activation of this enzyme. In this paper, we summarized the function of these residues in the oxygen activation, based on findings obtained by site-directed mutagenesis.

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In order to mate, male moths must find a female by flying or walking upwind, tracing a stream of dilute pheromones in the air. Recent research attempting to understand how information about the pheromones is processed in the olfactory neural system of the brain and how this information participates in generating and controlling orientation behavior, provides useful insight. The present review concerns with overview of odor orientation behavior and olfactory processing pathways of an insect brain, focusing on state-dependent of flipflopping neural sig- nals to repetitive pheromonal stimulation, which are important in controlling the behavior.

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Aggregation of insect larvae with secreting pheromone is studied by chemotaxis-random walk model (CR-model), in which the location of each individual is followed. If the number of individuals is mildly large (several tens), the model's behavior is different from the one predicted by the corresponding reaction-diffusion model (RD-model). Next, directed and random movement of a single cluster of animals is analyzed. Pheromone produced by a cluster tends to slow down the movement of the cluster. A formula for the magnitude of such effect (friction) is derived using approximation.

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Off-resonace irradiation effects were investigated using Bloch formalism, spin temperature and density matrix formalism. 1st model is suitable for the 1D off-resonance rotating frame experiments. 2nd model is important if dipolar order contributes to the relaxation process. 3rd model is used in the off-resonance ROESY (O-ROESY) experiment for the assessment of the internal motions of specific internuclear vectors.

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It is well known that time-resolved fluorescence of tryptophan in proteins frequently displays a non-exponential decay, even though the proteins contain only one tryptophan. It is also known that the tryptophan residue possesses a motional freedom in the proteins, as revealed by a time-resolved fluorescence anisotropy. In order to elucidate the mechanism underlying the non-exponential behavior on the intensity decay, we have solved a modified Smoluchowski equation into which an anguler-dependent quenching rate was introduced, and obtained theoretical expressions for both the time-resolved intensity and anisotropy. In the present paper we have described the results of the analysis on the motional-modes of internal motion of tryptophane in Streptomyces subtilisin inhibitor, on the basis of their picosecond time-resolved flouorescence intensity and anisotropy.

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