432 
Artificial  Diastase. 
f  Am.  Jour.  Pharm. 
I     August,  1889. 
AETIFICIAL  DIASTASE.1 
By  A.  Reychlee. 
When  freshly  prepared  wheat  gluten  is  digested  at  30-40°  for  a 
few  hours  with  very  dilute  acids,  considerable  quantities  of  albumin- 
oids are  dissolved,  forming  an  opalescent  solution.  The  acids  or  acid 
salts  employed  were  hydrochloric  acid,  hydrogen  potassium  sulphite, 
phosphoric  acid,  alkaline  dihydrogen  phosphates,  acetic  acid,  formic 
acid,  tartaric  acid,  and  lactic  acid. 
This  opalescent  solution  is  not  coagulated  by  boiling ;  it  gives  a  pre- 
cipitate with  a  few  drops  of  very  dilute  potash,  soluble  in  excess.  It 
becomes  clear  on  adding  two  volumes  of  alcohol,  but  a  turbidity  is 
generally  produced  when  the  alcohol  is  added  in  large  quantities.  It 
gives  a  precipitate  with  potassium  ferrocyanide,  soluble  in  a  large 
quantity  of  acetic  acid.  Mercuric  chloride  seems  to  produce  no  pre- 
cipitate. 
Tincture  of  guaiacum  and  hydrogen  peroxide  produce  an  intense 
blue  coloration,  but  not  if  the  solution  has  been  previously  boiled  or 
treated  with  too  much  acid.  A  solution  of  the  gluten  from  wheat 
flour  (10  grams)  in  acetic  acid  (tswo  50  cc),  gives  this  reaction  most 
distinctly.  This  behavior,  according  to  Lintner,  is  characteristic  of 
diastase. 
The  gluten  solutions  have  a  fermentive  action  similar  to  that  of 
diastase,  but  they  lose  their  property  partially  or  completely  when 
boiled,  or  in  presence  of  alkalis  or  of  too  much  acid.  The  gluten  from 
20  grams  of  wheat  flour  was  digested  for  a  few  hours  with  100  cc.  of 
an  aqueous  solution  (500  cc.)  of  potassium  dihydrogen  phosphate 
(1  gram).  2  cc.  of  the  solution  were  then  added  to  starch  (2  grams, 
88  per  cent.)  made  into  a  paste  with  water  (250  cc),  and  the  mixture 
kept  for  five  hours  at  40-50°.  The  solution  thus  obtained  reduced 
135  cc.  of  Soxhlet's  alkaline  copper  solution. 
The  soluble  albuminoids  present  in  wheat  flour  also  contain  dias- 
tase, as  can  be  proved  by  Lintner's  reaction.  Starch  (4  grams)  made 
into  a  paste  with  water  was  digested  for  two  hours  at  60-66°  :  (1) 
with  an  aqueous  extract  from  1'6  grams  of  wheat  flour,  and  (2)  with 
a  similar  extract  to  which  2  cc.  of  hydrochloric  acid  (nfao)  had  been 
added.  At  the  end  of  this  time  the  solutions  still  contained  unchanged 
starch,  and  reduced  100  cc.  and  210  cc.  of  Soxhlets  solution  respec- 
ter., xxii,  414-419;  from  Jour.  Chem.  Soc,  June,  p.  621. 
