PHOSPHOPROTEINS. 103 



an increase in the free OH ions produced by the salts. This view is not 

 tenable for several globulins, and seems in fact not to be well founded. 



That a sharp line cannot be drawn between the albumins and glob- 

 ulins follows from the fact that the albumins can be converted into glob- 

 ulins. The possibility of a conversion of ovalbumin into globulin is 

 based upon the observations of STARKE. That a transformation of 

 seralbumin into serglobulin with the aid of the weak action of alkali in the 

 warmth, with the splitting off of sulphur, can take place, has been more 

 conclusively shown by MOLL 1 by experimenting with blood-serum as 

 well as with crystalline seralbumin. According to MOLL, first pseudoglob- 

 ulin is formed from the seralbumin, and then euglobulin (see Chapter 

 VI) . The artificial globulins thus obtained had the same sulphur content 

 and properties as the natural products. 



It is evident that we are here dealing with a change of the external 

 properties of the albumins to a greater similarity to those of the glob- 

 ulins, and not with a true transformation of the albumin into globulin. 

 This follows from the fact that by the action of weak alkali upon albumin, 

 which is free from glycocoll, we do not obtain globulin which contains 

 glycocoll. This is an instructive example of the subordinate importance 

 the solubility and precipitation properties have in the differentiation of 

 various groups of proteids. 



It is just as difficult to draw a sharp line between the globulins and 

 albuminates as it is between the globulins and albumins. Several globu- 

 lins are very readily changed by the action of very little acid, as also by 

 standing under water when in a precipitated condition, into albuminates, 

 and then become insoluble in neutral salt solutions. OsBORNE, 2 who 

 has closely studied this property in connection with edestin (from hemp- 

 seed), considers the globulin, " globan," which has been made insoluble 

 in salt solution, as an intermediate step in the formation of the albumin- 

 ate which is produced by the hydrolytic action of the H ions of water 

 or of the acid. 



Phosphoproteins are a group of phosphorized proteids which occur 

 extensively in the animal and plant kingdoms and which include the 

 nudeoalbumins and the little-studied lecithalbumins. 



Nudeoalbumins. These proteids behave like rather strong acids, 

 are nearly insoluble in water, but dissolve easily with the aid of a little 

 alkali and, in the entire absence of lecithin, contain also phosphorus. 

 Certain of the nudeoalbumins resemble the globulins by their solubility 

 and precipitation properties. Others resemble the albuminates, but 

 differ from both of these groups by containing phosphorus. They stand 



1 Hofmeister's Beitrage, 4 and 7. 



2 Zeitschr. f. physiol. Chem., 33. 



