IN BOSTON

GENERAL HOSPITAL
BAKER MEMORIAL
PHILLIPS HOUSE

  HALL.MERCER HOSPITAL
HUNTINGTON MEMORIAL HOSPITAL
VINCENT MEMORIAL HOSPITAL

DEAN A. CLARK, M.D.
GENERAL DIRECTOR

Eioc hemic a1 Research Lab0 ratory
Ilovember 6, 195'0

IN WAVER LY

MC LEAN HOSPITAL

W. FRANKLIN WOOD. M.D.

DIRECTOR

T)r. Arthur Kornberg
Kational Institutes of iiealth
C. S. Public Health Service
Eethesda 14, hiawland

gear Arthur:

I hope you will foreive this long delay in answering your letter,

but I put it off from day to day hoping that I would be able tjo make some
definite statements concerning the nature of the adenylic acid in coenzyme
A.  However, the clarification of the picture is slower than 1 had antici-
pated, so I thought I woxld drcp `IOU a note concerning the progress to date.

First, I want to thank you for the kind qift of your nucleotidase.

The packape arrived in rather bad condition, the thernos was completel$
demolished (this I will replace for you), but fortunately, the vial of
enzyme was intact.
about 900 units/nl.
found that Co A Is spl-lt better at pIi 5.C than it is at pM 7.5.
difference which still remains to be emlairled.

I assaye6 it for DPld sglit-ling and found it to mntain
I made a fer; trials @E Co I! -xith your enzyme and again
                                  This is a

  I have been able to demonstrate that Co A has a free Fhosphate group
in addition to the kridge md if this proup is on the adenosine portion of
the molecule, then it would have certain similarities to TPK.
connection,  1. would like to ask you if you were able to determine how
adenosine diphosphate moves on paper xith respect to the other adenosine
mononucleotides?

-

In this

One difficulty that I have encountered is that the acid phosphatase

present in potato extracts strips t,he free phosphate group from Co A
during thg at.tack on the bridge.
in your TPK work.
an acetate buffer, which is near the optimum for the acid phosphatase,
while you viork at pH 7.5 and in phosphate buffer.  Have you determined
vhether the acid phosphatase is inhibited by phosphate?

I wonder how you avoided this difficulty

Gne possible explanation is that I work at pH 5.0 in

In several eperiments, I have been able to :ret evidence for the

appearance of some AW-5 after potato splitting.

The amount of ABF-5

-

To Dr. Arthur Kornberg

November 6, 1950

which cw1 be demonstrated is quite variable and never more than 0.6 pA:
per pivl of pantothenate. I believe that the potato acid phosphatase is
splitting some of the AE2-5 and I'm trying now to suppress the activity
of this phosphatase.

'de have been having rather good luck Taiith paper chromatography in

the purification of Co A. It now begins to look as if we will have some
rather pure material in the near future.  'ithen this becomes available, I
woiild like to know if it viould still be possible to accept your offer for
me to visit you for a few days.  At that the,  if it mill not be too
great an ircorxenience to you,  I would like to 50 over qy data with you
and perhaps repeat some cf the more critical experiments.

Please accept my belated congratulations on your winning of the

?aul Lewis Award.

Sincerely,

S. David Rovelli

SI)R : j 1