Characteristics of various synthetic peptide calpain inhibitors and their application for the analysis of platelet reaction

Calpeptin (a cell permeable synthetic peptide calpain inhibitor) inhibited the generation of thromboxane B2 (TxB2) by the direct inhibition on Tx synthetase in platelets at the concentrations more than 30 microM. Calpeptin, its analogues and E-64d (EST) were further examined with regard to cell permiability and inhibitory spectra. Among all compounds, only calpeptin inhibited the degradation of substrate proteins of calpain with negligible effect on TxB2 generation in intact platelets at the concentrations less than 30 microM. These concentrations of calpeptin did not inhibit the platelet aggregation, the elevation of [Ca2+], nor the formation of inositol 1,4,5-trisphosphate (IP3) in thrombin or collagen activated platelets. These results indicate that calpain dose not participate in the process of platelet activation induced by thrombin or collagen.     

The Nutritional Value of D-Amino Acid in the Chick Nutrition

The nutritional values of 16 D-amino acids in chick growth were studied on the purified diets containing crystalline amino acids as a sole source of nitrogen. Growth rate, feed consumption and nitrogen retention were measured. The nutritional values of D-amino acids were studied by comparing individually with the control groups fed on the diet containing all L-amino acids and negative control groups fed with the diet omitted the corresponding L-isomer. The following results were obtained. Essential amino acids: 1. Equal or almost equal nutritional value to the corresponding L-isomer; methionine, phenylalanine, leucine, proline. 2. Half nutritional value compared with L-isomer; valine. 3. Small nutritional value compared with L-isomer; tryptophan, isoleucine, histidine. 4. No nutritional value; lysine, threonine, arginine. Non-essential amino acid: 1. Equal or almost equal nutritional value to the corresponding L-isomer; serine, tyrosine, cystine. 2. There is a possibility that it has a slight growth retardation effect; alanine. 3. The growth retardation effect was found; aspartic acid.     

Genome-wide association study of idiopathic hypersomnia in a Japanese population

Sleep and Biological Rhythms - Idiopathic hypersomnia (IH) is a rare sleep disorder characterized by excessive daytime sleepiness, great difficulty upon awakening, and prolonged sleep time. In...     

Synthesis and characterization of the sweet protein brazzein

The sweet protein brazzein isolated from the fruit of the African plant, Pentadiplandra brazzeana Baillon is 2000-500 times sweeter than sucrose, and consists of 54 amino acid residues with four intramolecular disulfide bonds. Brazzein was prepared by the fluoren-9-yl-methoxycarbonyl solid-phase method, and was identical to natural brazzein by high performance liquid chromatography, mass spectroscopy, peptide mapping, and taste evaluation. The D enantiomer of brazzein was also synthesized, and was shown to be the mirror image of brazzein. The D enantiomer (ent-brazzein) was devoid of any sweetness and was essentially tasteless. © 1996 John Wiley & Sons, Inc.     

Unique CRF01_AE Gag CTL epitopes associated with lower HIV-viral load and delayed disease progression in a cohort of HIV-infected Thais

Cytotoxic T Lymphocytes (CTLs) play a central role in controlling HIV-replication. Although numerous CTL epitopes have been described, most are in subtype B or C infection. Little is known about CTL responses in CRF01_AE infection. Gag CTL responses were investigated in a cohort of 137 treatment-naïve HIV-1 infected Thai patients with high CD4+ T cell counts, using gIFN Enzyme-Linked Immunospot (ELISpot) assays with 15-mer overlapping peptides (OLPs) derived from locally dominant CRF01_AE Gag sequences. 44 OLPs were recognized in 112 (81.8%) individuals. Both the breadth and magnitude of the CTL response, particularly against the p24 region, positively correlated with CD4+ T cell count and inversely correlated with HIV viral load. The breadth of OLP response was also associated with slower progression to antiretroviral therapy initiation. Statistical analysis and single peptide ELISpot assay identified at least 17 significant associations between reactive OLP and HLA in 12 OLP regions; 6 OLP-HLA associations (35.3%) were not compatible with previously reported CTL epitopes, suggesting that these contained new CTL Gag epitopes. A substantial proportion of CTL epitopes in CRF01_AE infection differ from subtype B or C. However, the pattern of protective CTL responses is similar; Gag CTL responses, particularly against p24, control viral replication and slow clinical progression.     

Postsynaptic modulation of cholinergic transmission by endogenous substances

1. Recent concept of postsynaptic modulation is reviewed on the basis of literature data and the results of our investigation using conventional intracellular and voltage-clamp recording methods, in vitro. 2. Experimental evidence provided that the sensitivity of nicotinic ACh receptors endowed on the postsynaptic membrane of the bullfrog sympathetic ganglia and of the frog skeletal muscle end-plate is either facilitated or inhibited by other neurotransmitters or neurohormones. 3. We propose that one neurotransmitter not only initiates its own postsynaptic potential but also regulates the efficacy of synaptic transmission mediated by a distinct neurotransmitter, as an endogenous "antagonist" or "sensitizer".     

Activation of microsomal epoxide hydrolase by interaction with cytochromes P450: kinetic analysis of the association and substrate-specific activation of epoxide hydrolase function

The kinetics of the association between cytochrome P450 (P450) and microsomal epoxide hydrolase (mEH) was studied by means of resonant mirror based on the principle of surface plasmon resonance. The dissociation equilibrium constants (K(D)) for the affinity of P450 enzymes for mEH were estimated by resonant mirror using an optical biosensor cell covalently bound to rat mEH. Comparable K(D) values were obtained for CYP1A1 and 2B1, and these were greater by one order of magnitude than that for the CYP2C11. To clarify the influences of P450 enzymes on the catalytic activity of mEH, the hydrolyzing activity for styrene oxide and benzo(a)pyrene-7,8-oxide [B(a)P-oxide] was analyzed in the presence or absence of P450s. Styrene oxide hydrolysis was activated by all P450s including the CYP1A, 2B, 2C, and 3A subfamilies. In agreement with the association affinity determined by resonant mirror, CYP2C11 tends to have enhanced activity for styrene oxide hydrolysis. On the other hand, B(a)P-oxide hydrolysis was enhanced by only CYP2C11 while CYP1A1 and CYP2B1 had no effect. These results suggest that (1) many P450 enzymes associate nonspecifically with mEH, (2) the CYP2C11 plays a greater role in the association/activation of mEH and (3) the P450-mediated activation of mEH depends upon the substrate of mEH.