Biographical Memoirs Volume 63 (1994) / Chapter Skim
Currently Skimming:
17. John Howard Northrop
17. John Howard Northrop
Pages 422-451
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 423... ...
Columbia University with a huge chemistry building in his name. John's parents were Alice Rich Northrop anci~ohn Isaiah Northrop.
|
From page 424... ...
Despite this clevastating accident to her husband, Mrs. Northrop maintained a close association with both Columbia's Zoology Department and Hunter College while rearing her son.
|
From page 425... ...
Bayard Cutting Travelling Fellowship, but the turmoil in Europe end Jacques Loeb's acceptance of John to work at the Rockefeller Institute for Medical Research led him to forego the fellowship. This was an important decision because John retained an association with the Rockefeller Institute (later University)
|
From page 426... ...
they have three grown children, John H Northrop IT, Geoffrey Mason Northrop, and Helen Haskel Northrop.
|
From page 427... ...
with a plant pathologist in raising seed potatoes, in the summer months in Aroostook County, Maine. His work was selecting varieties or sources of potatoes that were not infected with disease agents, as juclgect by whether they procluced lesions on tobacco plants.
|
From page 428... ...
that inbreeding of aseptic drosophila for 230 generations in the clerk had no cliscernable effect on their life duration, fecundity, or resistance to harmful bacteria. John's work with I~oeb was halter!
|
From page 429... ...
Exposecl to multiple light sources, the crabs oriented themselves so the product of the intensity of the light, the time of exposure, and the cosine of the angle of incidence at the surface of the photosensitive organ were equal for each light source. In other work he studied Donnan equilibria; the kinetics of osmosis; the swelling of cells; anti, with Moses Kunitz, the micelIar nature of gelatin.
|
From page 430... ...
I found that neither pepsin nor trypsin are taken up by living organisms, whereas as soon as the organisms die, the enzyme rapidly digests them. Live fish or worms may live in the presence of pepsin or trypsin strong enough to digest the dead organism in a few hours." Jacques Loeb's sudden death in 1924 brought to a close an important period in Northrop's life.
|
From page 431... ...
His evidence consisted of a number of attempts to separate the enzymic activity from the protein, all of which failed. He fractionated crystalline pepsin by recrystallization, salt fractionation, pH, heat, or radiation inactivation in which initial and final fractions were assayed for their enzymic activity per milligram of protein.
|
From page 432... ...
not rule out the case of pepsin being two closely related proteins but then he noted, "It seems reasonable to conclude from these experiments that the possibility of a mixture must be limited to a mixture of proteins, so that the conclusion seems justif~ecl that pepsin itself is a protein." In 1933 workers in two European laboratories reported adsorbing peptic activity onto melon seed proteins. One writer interpreted this as a transfer of the "active group" of pepsin to the seed protein, as expected from their view of enzymes.
|
From page 433... ...
Daily discussions with Northrop finally led to its isolation in crystalline form. Similar fractionation and solubility studies failecl to separate the tryptic activity from the protein.
|
From page 434... ...
in acldition to the diffusion cell and the solubility diagram procedures, he clesignecl electrical panels for close temperature control of incubators and water baths. He proclucecl micro ant!
|
From page 435... ...
He precipitated the phage from 200 liter quantities of lysate, followed by salt fractionation and solubility studies of the phage. Northrop found nucleic acid in his purest phage preparations, a finding
|
From page 436... ...
These independent observations of nucleic acid in phages and Bawden and Pirie's discovery of RNA in tobacco mosaic virus were only highly suggestive at the time, since the function of nucleic acids was not understood then. This gap in the knowledge of the function of nucleic acids led Northrop, unfortunately, to suggest that phage, like pepsin and trypsin, may be derived from precursor protein in the host cells.
|
From page 437... ...
This was passed to the British defense which in due time replied with a polite "thank you for your valuable suggestion" and nothing more. After the war Northrop react in one of Churchill's books, "There will be no more mass bombing raids, since a defense has been founcl: small explosive charges suspendecl from small parachutes." POSTWAR ACTIVITIES In the years following WorIct War IT a number of events were to influence John H
|
From page 438... ...
~ am surprised that Northrop (lic3 not make more of de Jong's experiment. However, in the closing sentence of one of his late papers, Northrop correctly suggested the nature ~ 7
|
From page 439... ...
Northrop devoted many months of research to showing that the rate of induction of lysogenic cells to form phage was comparable to the rates of mutation of these cells to antibiotic or phage resistance. He and Kunitz found that his data conformed to the theoretical expression developed for the formation of mutants.
|
From page 440... ...
of enzymes. As John Edsall wrote "John Northrop probably clicl more than any one other indiviclual to establish that pure enzymes are indeed proteins." In view of the involvement of enzymes in virtually all biological reactions, establishing their chemical nature was a scientific contribution of the first magnitude.
|
From page 441... ...
5. The discovery in 1982-83, by Thomas Cech and Sidney Altman, that certain RNAs have catalytic properties modifies the generally held belief that all enzymes are proteins.
|
From page 442... ...
Stanley 1948 The President's Certificate of Merit 1949 Columbia University Lion Award Alumni Club of Essex County 1961 The Alexander Hamilton Award, Columbia University
|
From page 443... ...
JOHN HOWARD NORTHROP SELECTED BIBLIOGRAPHY 443 1916 With i.
|
From page 444... ...
The inoculation of tomato and tobacco plants with potato mosaic virus. Science 61:544-45.
|
From page 445... ...
III. Preparation of active crystalline pepsin from inactive denatured pepsin.
|
From page 446... ...
V 1933 Isolation of crystalline pepsin from bovine gastric juice.
|
From page 447... ...
I Isolation of crystalline pepsin of constant activity and solubility from pepsinogen or commercial pepsin preparations.
|
From page 448... ...
Appearance of new phage types and new lysogenic strains after adaptation of lysogenic Bacillus megathera? ~m to ammonium sulfate culture medium.
|
From page 449... ...
VII. The effect of various mutagens (urethane, ethyl urethane, hydrogen peroxide, desoxycholate, maleic hydrazide, butadiene dioxide, triethylene melamine, versene, and acriflavine)
|
From page 450... ...
cold cultures after prolonged growth in the presence of triethylene melamine.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.