570 
Action  of  Papain. 
j  Am.  Jour.  Pharm. 
t      Nov.,  1885. 
In  the  present  investigation  I  attempted  to  settle  this  point.  In  the 
first  place,  the  body  called  a  peptone"  in  my  previous  paper  is  not  a 
true  peptone — that  is,  a  proteid  capable  of  fairly  rapid  diffusion,  not 
precipitated  by  nitric  nor  by  acetic  acid  and  ferrocyanide  of  potassium  ; 
but  it  is  one  of  the  bodies  intermediate  between  globulins  and  peptone, 
first  described  by  Meissner  as  a  peptone,  and  called  by  Kuhne  hemi- 
albumose.  This  body  agrees  with  peptone  in  the  following  reactions: 
It  is  soluble  in  distilled  water,  and  is  not  precipitated  from  this  solu- 
tion by  boiling;  it  also  gives  a  pink  or  red  color  with  copper  sulphate 
and  excess  of  potash.  It  differs  from  peptone  in  being  precipitated  by 
strong  mineral  acids,  and  by  acetic  acid  and  ferrocyanide  of  potassium. 
Tliese  reactions  agree  with  those  given  by  Wurtz  as  characteristic  of 
solutions  of  pure  papain  ;  this  agreement,  indeed,  led  me  to  think  that 
the  ferment  was  associated  with  tlie  hemialbumose.  I  found  this  to' 
be  the  case.  A  glycerin  extract  was  made  of  commercial  papain,  the 
glycerin  being  filtered  clear  under  pressure.  This  extract  contained  a 
proteid  (hemialbumose)  in  quantity  and  a  mere  trace  of  globulin.  It 
was  as  active  as  the  powder  itself.  Part  of  this  extract  was  diluted 
with  water,  and  saturated  with  magnesium  sulphate  to  precipitate  the 
small  amount  of  globulin,  which  was  filtered  off;  the  filtrate  was  then 
saturated  with  sodium  sulphate,  which  precipitated  the  hemialbumose. 
This  was  collected  on  a  filter,  washed  with  a  saturated  solution  of  sodio- 
magnesium  sulphate,  and  then  dissolved  in  water.  This  solution  of 
the  precipitated  hemialbumose  was  found  to  be  very  active ;  it  was 
tested  witli  coagulated  egg  albumen,  peptones  being  formed  in  quan- 
tity. The  filtrate,  after  saturation  with  sodium  sulphate,  contained  a 
little  hemialbumose.  After  dialyzing  for  some  hours,  its  action  was 
tested  on  egg  albumen  ;  very  little,  if  any.  digested.  This  experiment 
distinctly  shows  that  the  ferment  action  is  associated  with  the  hemial- 
bumose. 
The  result  was  confirmed  in  another  experiment,  in  which  a  similar 
process  of  saturation  was  performed  in  a  watery  solution  of  papain. 
The  result  may  be  tabulated  as  follows : 
Precipitate  by  magnesium 
sulphate  =  globulin. 
Precipitate  by  sodium  sul- 
phate =  liemialbumose. 
Filtrate  containing 
no  proteid. 
No  action  on  coagulated 
egg  albumen   at  35"  to 
40°C. 
Forms  peptones  from  coag- 
ulated egg  albumen  at  35° 
to  40°C. 
No  action  on  albumen  at 
35°  to  40°C. 
