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홍남주,진동훈,Eun Young Hong 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.3
A series of conjugated cyclic and linear enkephalin analogs, Tyr-c[D-A2bu-Gly-Phe-Asp(NH-X)], where X = methyl, stearyl or PEG350, and Tyr-D-Ala-Gly-Phe-Cys(S-X), where X = methyl, octyl, or farnesyl, were synthesized in solution to investigate the receptor selectivity of opioids based on Schwyzer's membrane compartment concepts.5,6 Cyclizations of the target compounds were achieved in high yields (> 60%) employing BOP, NaHCO3 in DMF despite the steric hindrance of the bulky pendant groups. In the binding assay, the hydrophobic fatty acyl conjugates retained μ-receptor selectivity. The unsaturated farnesyl conjugate exhibited the increased binding affinity than the saturated stearyl conjugate for both μ-and δ-opioid receptors. The PEG conjugates displayed the δ-receptor selectivity. The low molecular weight PEG350 conjugate exhibited the increase selectivity than the high molecular weight PEG5000 conjugate to the δ-receptor. The results of this study support the membrane compartment concepts.
안희준,김형진,홍남주,진동훈 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.7
A new and relatively simple spectrophotometric technique has been developed for the accurate determination of α-factor pheromone affinities for Ste2p whole cell receptor in yeast a-cells. We designed and tested nine detector peptides containing mono- (ε412 = 14 500) or tri-cysteine residues (ε412 = 43 660). The free unbound detector was detected using Ellman's reagent at 412 nm. Saturation binding studies using Saccharomyces cerevisiae Y 7925 (MATa ) at a concentration of 2.5 × 1011 cells/mL with the highest affinity detector 1, [Orn6]α-factor-[Cys]3, resulted in a dissociation constant ( K D ) of 1.67 × 10−7 and total binding sites per cell (B cell = 29 500 sites/cell) comparable with those obtained using radiolabeled binding assays. Competitive binding assay using five nonchromogenic α-factor analogs allowed for the determination of each K D value. [Orn6,d-Ala9]α-factor showed the highest receptor affinity ( K D = 1.03 × 10−7 M), which was threefold higher than that of native α-factor. This assay provides rapid and convenient results for determining the relative affinities of nonchromogenic α-factors and eliminates the need for radioactive waste disposal.
Highly Active Analogs of α-Factor and Their Activities Against Saccharomyces cerevisiae
Hee Jun Ahn,Eun Young Hong,진동훈,홍남주 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.5
Thirteen analogs of tridecapeptide α-factor (WHWLQLKPGQPMY) of Saccharomyces cerevisiae with C- or N-terminal Trp extension and isosteric replacement by Aib at position 8 and 11, Trp at position 13, D-Ala at position 9, and Orn and Glu at position 6 were synthesized and assayed for their biological activity. Receptor binding assay was carried out using our newly developed spectrophotometric method with detector peptide 14. C- or N-terminal extended analogs, α-factor-[Trp]n (n =1-5) 1-5 and [N-Trp]1-α-factor 6, were all less active than native α-factor and gradual decreases in both activity and receptor affinity were observed with greater Trp extension. Trp-substituted analog at position 13, [Trp13]α-factor 7, exhibited about 2-fold reductions in both activity and receptor affinity. Aib-substituted analogs, [Aib8]α-factor 8 and [Aib11]α-factor 9, showed 5- to 10- fold reduction in activity as well as 3-fold reduction in receptor affinity compared to native α-factor. [Orn6]α- factor 10 demonstrated strong potency with a 7.0-fold increase in halo activity as well as 1.8-fold increase in receptor affinity compared to native α-factor. For two double substituted analogs, [Glu6,D-Ala9]α-factor 12 showed the slightly decreased potency in halo activity compared to analog 10, whereas [Orn6,D-Ala9]α-factor 11 exhibited 15-fold higher halo activity as well as nearly 3-fold higher receptor affinity compared to native α-factor.