26062-48-6Relevant articles and documents
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Deulofeu,Mitta
, p. 915,918 (1948)
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Reduction potential of histidine free radicals: A pulse radiolysis study
Navaratnam,Parsons
, p. 2577 - 2581 (1998)
The technique of pulse radiolysis has been used to demonstrate that all histidine free radicals (designated His.+) produced by oxidation of histidine by Br2.- radical anions can oxidise the water soluble vitamin E analogue, Trolox C (k = 1.0 ± 0.2 × 109 dm3 mol-1 s-1 at pH 6.95). It has also been shown that His.+ radicals can react with tryptophan in electron transfer equilibria involving both His.+ and Trp.+ species over the pH range 6.4-9.0. The ΔE values [E(Trp.+/Trp) - E(His.+/His)] range from -140 to -161 mV and indicate an E7(His.+/His) value of 1170 mV [based on E7(Trp.+/Trp) = 1015 mV at pH 7]. The effect of pH on E(His.+/His) was accounted for by assuming that His.+ can deprotonate to yield a bi-allylic free radical, designated His (-H+).. The pKa for this dissociation was estimated to be in the range 5-7. The implications of the relatively high reduction potential for His.+ in its possible participation in the mechanism of action of non-heme metalloenzymes is discussed.
Chromatographic Resolution of α-Amino Acids by (R)-(3,3'-Halogen Substituted-1,1'-binaphthyl)-20-crown-6 Stationary Phase in HPLC
Wu, Peng,Wu, Yuping,Zhang, Junhui,Lu, Zhenyu,Zhang, Mei,Chen, Xuexian,Yuan, Liming
supporting information, p. 1037 - 1042 (2017/07/25)
Three new chiral stationary phases (CSPs) for high-performance liquid chromatography were prepared from R-(3,3'-halogen substituted-1,1'-binaphthyl)-20-crown-6 (halogen = Cl, Br and I). The experimental results showed that R-(3,3'-dibromo-1,1'-binaphthyl)-20-crown-6 (CSP-1) possesses more prominent enantioselectivity than the two other halogen-substituted crown ether derivatives. All twenty-one α-amino acids have different degrees of separation on R-(3,3'-dibromo-1,1'-binaphthyl)-20-crown-6-based CSP-1 at room temperature. The enantioselectivity of CSP-1 is also better than those of some commercial R-(1,1'-binaphthyl)-20-crown-6 derivatives. Both the separation factors (α) and the resolution (Rs) are better than those of commercial crown ether-based CSPs [CROWNPAK CR(+) from Daicel] under the same conditions for asparagine, threonine, proline, arginine, serine, histidine and valine, which cannot be separated by commercial CR(+). This study proves the commercial usefulness of the R-(3,3'-dibromo-1,1'-binaphthyl)-20-crown-6 chiral stationary phase.
INSULIN PREPARATIONS CONTAINING METHIONINE
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, (2012/10/08)
The invention relates to an aqueous pharmaceutical formulation having insulin, an insulin analog, or an insulin derivative, and methionine; and to the production thereof, to the use thereof for treating diabetes mellitus, and to a medication for treating diabetes mellitus.