ORD studies

Jirgensons 365) has made the intriguing suggestion based on ORD studies of a number of proteins that detergents induce the formation of helical structure from either unordered or / structures. 

Bohr, H., and Bohr, J. 2000. Microwave enhanced kinetics observed in ORD studies of a protein. Bioelectromagnetics 27 68-72. 

Lindskog and Malmstrom (1962) first succeeded in removing the zinc under sufficiently mild conditions to avoid denaturation. The zinc was complexed with phenan-throline and the resulting complex removed by dialysis. The apoenzyme was catalytically inactive and the activity could be restored by addition of one mole of zinc per mole of apoenzyme. ORD studies have shown that the apoenzyme and the native enzyme have the same gross teriary structure, confirming that the function of the zinc is not to stabilise the tertiary structure, but it is directly involved in the catalytic activity of the enzyme. 

The solubility of a number of proteins in NMA was investigated by Rees and Singer232. Of these insulin and j3-lactoglobulin were found to be soluble to at least one gram per liter while zein is soluble to at least ten grams per liter233). An ORD study of zein in NMA233) led to the conclusion that the helicity (28 °C) is 42%. 

Based upon ORD studies on 78 and on the stereochemical outcome of the reaction of 76 with oc-phenylbutyric anhydride it was concluded... 

ORD-Studies show that argemonine has the absolute structure LXXXIX (157a) and this structure has been confirmed by its degradation to a derivative of L-aspartic acid (157b). Later optical methods confirmed this (158). Finally, ORD- and CD-measurements show that, except for (-f )-0-methylcaryachine, the known alkaloids which have the... 

Experimental. All the ORD studies were made with paramyosin prepared from the white portion of the adductor muscle of the clam Venus mercenaria, as outlined by Riddiford and Scheraga (47). The experimental procedure has been given in detail (46). All ORD measurements were made on the Cary model 60 recording spectropolarimeter at 23° =b 2°C., except as otherwise noted. 

ORD-studies conducted on colchicine derivatives, colchinols, and ]8-and y-lumicolchicine (Table II) have clarified some of the stereochemical aspects of these molecules (28). Colchinol (XIX) and its derivatives are essentially bridged and skewed biphenyls. They show a single strong negative Cotton effect at 260 mp which implies an S-configuration (XX), also indicated in the X-ray analysis of colchicine (XXI). 

The absolute configuration of lycopodine, and therefore of annofoline and acrifoline, was arrived at independently by Wiesner et al. (76) and by Burnell and Taylor (92) from ORD-studies on the alkaloid. It is that shown in the structural formulas of these alkaloids. 

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