Skip to main contentU.S. National Library of MedicineU.S. National Library of Medicine

Profiles in Science
Pinterest badge Follow Profiles in Science on Pinterest!

The Sol Spiegelman Papers

Letter from Joshua Lederberg to Sol Spiegelman pdf (97,901 Bytes) transcript of pdf
Letter from Joshua Lederberg to Sol Spiegelman
Number of Image Pages:
2 (97,901 Bytes)
1946-11-06 (November 6, 1946)
Lederberg, Joshua
[Spiegelman, Sol]
This item is in the public domain. It may be used without permission.
Medical Subject Headings (MeSH):
Exhibit Category:
Enzymes and Genetics, 1940-1955
Metadata Record Letter from Sol Spiegelman to Joshua Lederberg (November 11, 1946) pdf (157,116 Bytes) transcript of pdf
Box Number: 6
Folder Number: 42
Unique Identifier:
Document Type:
Letters (correspondence)
Physical Condition:
Series: Correspondence, 1946-1983
Folder: Lederberg, Joshua, 1946-1978
November 6, 1946.
Dear Sol:
How's the Genius? (That is Leewi's description; I heard it with my own ears this summer at Woods Hole.)
Bonner just let me see a copy of your manuscript, and reading it was just like being at Cold Spring Harbour, hearing one line of evidence after another until one is almost compelled to say: Stop, I'll believe anything you say. It is quite thrilling. Anything new?
There is only one point which is not quite clear to me, and that is the detail of the postulated mechanism of substrate-enzyme interactions, particularly between different systems. What, do you propose is the mechanism by which the formation of a second enzyme depletes the first; why should the presence of exogenous N affect this process if the substrates are simply competing on unstable enzyme molecules? Why are the enzymes less unstable in the presence of azide? All of these questions are based on this conception of the role of substrate: that the precursor suffers random reversible changes, o ccasionally producing enzymatically specific molecules, and that these are stabilized by the presence of the substrate. However, it is difficult for me to see the role of a second 'competing substrate' in effecting changes in the rate of the reaction of decomposition from E to Pr. Perhaps this is too simplified the conception; I would appreciate it if you could clarify it for me.
You may be interested that a preliminary note on our bacterial work has appeared in Nature for Oct. 19. I'm climbing on your bandwagon, in a way; in hopes of finding non Mendelian mechanisms to account for certain discrepancies in the ratios of the various new types that appear in our mixed cultures, we are going to look at the inheritance of a lactose fermentation character; E. coli (a triple mutant Y-10) was heavily irradiated, and after preliminary cultivation, was spread out on EMB-lactose plates. 1/20,000 colonies was a non-fermenter, and we are going to study the segregation of this character into prototrophs when Y-10-L- and another biochemical mutant which is Lplus are crossed, in the presence and absence of lactose. Any suggestions?
Well, best of luck, in regards to everybody there,
Metadata Last Modified Date:
Linked Data:
RDF/XML     JSON     JSON-LD     N3/Turtle     N-Triples