SEP *B 1962

UNIVERSITY OF PITTSBURGH
GRADUATE SCHOOL OF PUBLIC HEALTH

PITTSBURGH 13. PENNSYLVANIA

DEPARTMENT OF
BIOCHEMISTRY AND NUTRITION

September 5, 1962

Dr. Joshua Lederberg

Department of Genetics ;

School of. Medicine 4 ees
Stanford University Medical Centcr

Palo Alto, California

Dear Professor Lederberg,

I was interested to receive a copy of your note of August 29th

to Dr. Jerzy Brahms of the University of Alberta Medical School.
We have been most interested in the recent publication in the
Journal of Molecular Biology of Brahms and Kay to which your
letter alludes. Our own previous work on the molecular parameters
of cardiac myosin have pointed toa considerably lower particle
weight of about 250,000 for cardiac myosin. More recent work in
our laboratory, however, has suggested that the true particle size
of "ordinary" cardiac myosin is probably of twice that, about
500,000. This figure agrees very well with the particle estimates
for normal skeletal myosin and is appreciably lower than the value
reported by Brahms and Kay.

Furthermore, there is no doubt in our minds that cardiac and
skeletal myosin are different in other respetts. There is additional
immuno-chemical evidence of differences to that of Dr. Ogawa's

as well as marked different ATP-ase activity and altered resistance
of cardiac myosin to the action of trypsin.

We expect to continue to study this problem for sometime to come
with particular reference to changes which occur in connection with
cardiac failure in experimental animals and in human subjects. I
would be most pleased to put you on our reprint list if you would be
interested in following this work.

Ver¥)sine erely yours,

bE CC

: { af Let ©
Robert BE. Olson, M.D..

Erotessor and Head of the Department

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