Part 8 (2/2)
H_{2}SO_{4} destruction was almost complete. In these cases there was no question of a mere oxidation to oxyluciferin, as no oxyluciferin could be demonstrated after boiling with such strong acids. An actual destruction, probably an hydrolysis of the luciferin molecule, occurred.
We shall have occasion to refer to this again in considering the protein nature of luciferin. It must be borne in mind that many proteins require four or five days' boiling with 20 per cent. HCl for complete hydrolysis to amino-acids. Luciferin forms a solution in water, probably colloidal, although the luciferin will dialyze through parchment or collodion membranes. It is rather readily adsorbed by various finely divided materials such as bone black, Fe(OH)_{3}, kaolin, talc and CaCo_{3}. It is not destroyed by any of the enzyme solutions which I have tried.
These include such as are widely divergent in action: pepsin HCl, trypsin, erepsin, salivary and malt diastase, yeast invertase, urease, rennin and the enzymes of dried spleen, kidney and liver substances.
By extracting the dried Cypridinas ground to a powder, the solubility of luciferin in non-aqueous solvents could be easily studied, and by adding such reagents as dilute acids, alkalies, neutral salts and the alkaloidal reagents to an aqueous solution of luciferin the general biochemical behavior of luciferin can be quite accurately stated. For convenience the results of this study are given in Table 8.
TABLE 8
_Properties of Photogenic Substances from Cypridina_
========================================================================= Property
Luciferase
Luciferin ------------------------+-----------------------+------------------------ _Salting out_
By saturation NaCl
Not precipitated
Not precipitated.
By half saturation
Do.
Do.
MgSO_{4}
By saturation MgSO_{4}
Nearly completely
Partially
precipitated
precipitated.
By saturation MgSO_{4}
...
Do.
+ acetic acid
By half saturation
(NH_{4})_{2}SO_{4}
Slightly precipitated
Not precipitated.
By saturation
Completely precipitated
Nearly completely (NH_{4})_{2}SO_{4}
precipitated.
By saturation
(NH_{4})_{2}SO_{4} +
...
Nearly completely acetic acid
precipitated.
_Solubility in_
Methyl alcohol
Insoluble
Soluble.
Ethyl alcohol
Do.
Do.
90 per cent.
Do.
Do.
70 per cent.
Do.
Do.
50 per cent.
Slightly soluble
Do.
Propyl alcohol
Insoluble
Do.
Isobutyl alcohol
Do.
Fairly soluble.
Amyl alcohol
Do.
Slightly soluble.
Benzyl alcohol
Do.
Soluble.
Acetone
Do.
Fairly soluble.
90 per cent.
Do.
Soluble.
70 per cent.
Slightly soluble
Do.
50 per cent.
Fairly soluble
Do.
Ethyl acetate
Insoluble
Do.
Ethyl propionate
Do.
Fairly soluble.
Ethyl butyrate
Do.
Do.
Ethyl valerate
Do.
Slightly soluble.
Ethyl nitrate
Do.
Very slightly soluble.
Glycerine
Do.
Soluble.
Glycol
Do.
Do.
Ether
Do.
Insoluble.
Chloroform
Do.
Do.
Carbon disulfide
Do.
Do.
Carbon tetrachloride
Do.
Do.
Benzol
Do.
Do.
Toluol
Do.
Do.
Xylol
Do.
Do.
Petroleum ether
Do.
Do.
Anilin
Do.
Do.
Glacial acetic acid
Do.
Fairly soluble.
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