448 PRACTICAL ORGANIC AND BIO-CHEMISTRY 



Properties. 



One of the chief differences between these proteins is their temperature of 

 heat coagulation. Paramyosinogen coagulates at 47; myosinogen at 56'. 



The extract obtained from fresh muscle on heating will coagulate at about 

 47 and after filtering off the flakes of protein it will coagulate again at about 

 56. (Coagulation may take place at about 40. This is the coagulation 

 temperature of soluble myosin formed from myosinogen.) 



Paramyosinogen is a typical globulin; it is insoluble in water and is 

 precipitated by half-saturation with ammonium sulphate. Myosinogen is an 

 atypical globulin ; it is soluble in water and is only partially precipitated by 

 half-saturation with ammonium sulphate. It resembles an albumin very 

 closely. 



They give the general reactions for proteins. 



Paramyosinogen from Dead Muscle. 



Preparation. 



The residue after the above extraction of paramyosinogen and 

 myosinogen is ground up with sand and treated with five volumes of 

 10 or 1 5 per cent ammonium chloride solution. The liquid is strained 

 from sand and insoluble protein. 



On dialysis it yields a precipitate of paramyosinogen, which is purified by 

 re-solution in salt solution and dialysis. 



Properties. 



The properties of paramyosinogen can be well seen with the above 

 extract : 



(1) Insolubility in water. On pouring some of the solution into 

 a large volume of water it is precipitated : the liquid is decanted off. 

 The remaining suspension is : 



(2) Soluble in dilute sodium chloride and precipitated on saturating 

 with sodium chloride. 



(3) Soluble in dilute ammonium sulphate and precipitated by half- 

 saturation with ammonium sulphate. 



(4) Coagulated at about 47 when dissolved in dilute ammonium 

 sulphate. 



Mjnosin. 



Myosin is insoluble in water and dilute salt solutions and remains 

 as a residue with the connective tissue. It has the properties of a co- 

 agulated protein and dissolves on warming in dilute acids and alkalies, 

 giving solutions of the metaprotein, syntonin. 



