Spectra of sodium and potassium azide crystals coloured by ultra-violet and X -ray radiation

1959 ◽  
Vol 251 (1264) ◽  
pp. 27-40 ◽  
Keyword(s):  
Sodium Salt ◽  
Ultra Violet ◽  
Liquid Nitrogen Temperature ◽  
Mechanism Of Formation ◽  
Potassium Salts ◽  
Absorption Bands ◽  
X Ray ◽  
Rate Of Increase ◽  
Potassium Azide ◽  
Sodium And Potassium

The spectra of sodium and potassium azide crystals that had been coloured by irradiation with both ultra-violet and X-ray radiation for varying periods at liquid-nitrogen temperature have been recorded. From these results and from measurements of the rate of increase of intensity of the various absorption bands with time, together with the changes observed on raising the temperature, the nature and mechanism of formation of some of the centres are deduced. The different behaviour of the sodium and potassium salts under irradiation and the different effects produced by the two types of irradiation, particularly with the sodium salt, are discussed.

Synthesis of Sulfoquinovose and Sulfoquinovosyl Diacylglycerides, and a Fluorogenic Substrate for Sulfoquinovosidases

2019 ◽  
Author(s):  
Yunyang Zhang ◽  
Janice Mui ◽  
Thimali Arumaperuma ◽  
James P. Lingford ◽  
ETHAN GODDARD-BORGER ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Fluorogenic Substrate ◽  
Potassium Salts ◽  
X Ray ◽  
Sulfoquinovosyl Diacylglycerol ◽  
Sodium And Potassium

<p>The sulfolipid sulfoquinovosyl diacylglycerol (SQDG) and its headgroup, the sulfosugar sulfoquinovose (SQ), are estimated to harbour up to half of all organosulfur in the biosphere. SQ is liberated from SQDG and related glycosides by the action of sulfoquinovosidases (SQases). We report a 10-step synthesis of SQDG that we apply to the preparation of saturated and unsaturated lipoforms. We also report an expeditious synthesis of SQ and (<sup>13</sup>C<sub>6</sub>)SQ, and X-ray crystal structures of sodium and potassium salts of SQ. Finally, we report the synthesis of a fluorogenic SQase substrate, methylumbelliferyl a-D-sulfoquinovoside, and examination of its cleavage kinetics by two recombinant SQases.</p>

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