MYOSIN, MUSCULIN. 541 



myosin separates as fibres, or if a myosin solution with a minimum 

 quantity of alkali is allowed to evaporate to a gelatinous mass on a 

 microscope-slide, doubly refracting myosin may be obtained. Myosin 

 has the general properties of the globulins. It is insoluble in water, but 

 soluble in dilute saline solutions as well as in dilute acids or alkalies, 

 which readily convert it into albuminates. It is completely precipitated 

 upon saturation with NaCl, also by MgSO 4 , in a solution containing 

 94 per cent of the salt with its water of crystallization (HALLIBURTON). 

 The precipitated myosin readily becomes insoluble. Like fibrinogen it 

 coagulates at 56 C. in a solution containing common salt, but differs 

 from it, since under no circumstances can it be converted into fibrin. 

 The coagulation temperature, according to CHITTENDEN and CUMMINS, 

 not only varies for myosins of different origin, but also for the same myosin 

 in different salt solutions. 



Myosin may be prepared in the following way, as suggested by HALLI- 

 BURTON: The muscle is first extracted by a 5-per cent magnesium- 

 sulphate solution. Tne filtered extract is then treated with magnesium 

 sulphate in substance until 100 cc. of the liquid contain about 50 grams 

 of the salt. The so-called paramyosinogen or musculin separates. The 

 filtered liquid is then treated with magnesium sulphate until each 100 cc. 

 of the liquid hold 94 grams of the salt in solution. The rnyosin which 

 now separates is filtered off, dissolved in water by aid of the retained 

 salt, precipitated by diluting with water, and, when necessary, purified 

 by redissolving in dilute salt solution and precipitating with water. 



The older and perhaps the usual method of preparation consists, 

 according to DANILEWSKY/ in extracting the muscle with a 5-10-per cent 

 ammonium-chloride solution, precipitating the myosin from the filtrate 

 by strongly diluting with water, and redissolving the precipitate in ammo- 

 nium-chloride solution, and the myosin obtained from this solution is 

 reprecipitated either by diluting with water or by removing the salt 

 by dialysis. 



Musculin, 2 called PARAMYOSINOGEN by HALLIBURTON, and MYOSIN 

 by v. FURTH, is a globulin which is characterized by its low coagulation 

 temperature, in frogs below 40, in mammalia 42-48, and in birds about 

 51 C., and which may vary in different species of animals. It is more 

 easily precipitated than myosin by NaCl or MgSC>4 (50 per cent salt, 

 including water of crystallization). According to v. FURTH it is precipi- 

 tated by ammonium sulphate with a concentration of 12-24 per cent 

 salt. If the dead muscle is extracted with water a part of the musculin 



1 Zeitschr. f. physiol. Chem., 5, 158. 



2 As we have up to the present no conclusive basis for the identity of the globulins 

 called myosin and paramyosinogen, and also as the use of the name myosin for the 

 last-mentioned substance may readily cause confusion, the author does not feel 

 justified in dropping the old name musculin (Nasse). 



