physics

John Howard Northrop

John Howard Northrop is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand John Howard Northrop rather than just read about it. In short: John Howard Northrop (July 5, 1891 – May 27, 1987) was an American biochemist who, with James Batcheller Sumner and Wendell Meredith Stanley, won the 1946 Nobel Prize in Chemistry. The award was given for these scientists' isolation, crystallization, and study of enzymes, proteins, and viruses.

Key takeaways

John Howard Northrop belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect John Howard Northrop to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of John Howard Northrop from memory before moving on to harder problems.

Reference excerpt

John Howard Northrop (July 5, 1891 – May 27, 1987) was an American biochemist who, with James Batcheller Sumner and Wendell Meredith Stanley, won the 1946 Nobel Prize in Chemistry. The award was given for these scientists' isolation, crystallization, and study of enzymes, proteins, and viruses. Northrop was a Professor of Bacteriology and Medical Physics, Emeritus, at University of California, Berkeley.

Biography

Early years Northrop was born in Yonkers, New York, to John Isaiah, a zoologist and instructor at Columbia University who is a member of the Havemeyer family, and Alice Rich Northrop, a teacher of botany at Hunter College. His father died in a lab explosion two weeks before John H. Northrop was born. The son was educated at Yonkers High School and Columbia University, where he earned his BA in 1912 and PhD in chemistry in 1915. During World War I, he conducted research for the U.S. Chemical Warfare Service on the production of acetone and ethanol through fermentation. This work led to studying enzymes.

Research In 1929, Northrop isolated and crystallized the gastric enzyme pepsin and determined that it was a protein. For this achievement, he was elected to the United States National Academy of Sciences in 1934. In 1938 he isolated and crystallized the first bacteriophage (a small virus that attacks bacteria), and determined that it was a nucleoprotein. He was elected to the American Philosophical Society that same year. Northrop also isolated and crystallized pepsinogen (the precursor to pepsin), trypsin, chymotrypsin, and carboxypeptidase. For his 1939 book, Crystalline Enzymes: The Chemistry of Pepsin, Trypsin, and Bacteriophage, Northrop was awarded the Daniel Giraud Elliot Medal from the National Academy of Sciences. He was elected a Fellow of the American Academy of Arts and Sciences in 1949. Northrop was employed by the Rockefeller Institute for Medical Research in New York City from 1916 until his retirement in 1961. In 1949 he joined the University of California, Berkeley as Professor of Bacteriology, and later, he was appointed Professor of Biophysics.

Personal life In 1917, Northrop married Louise Walker (1891–1975), with whom he had two children: John, an oceanographer, and Alice, who married Nobel laureate Frederick C. Robbins. The family lived in a small home just outside of Mt. Vernon, New York. As their children grew older and Northrop looked for a more desirable workplace, the family bought a home in Cotuit, Massachusetts. This move shortened Northrop's commute to the laboratory in Princeton, New Jersey, and also put him in closer contact with the wilderness which he greatly enjoyed. Northrop committed suicide in Wickenburg, Arizona in 1987.

References

Further reading Economos, A. C.; Lints, F. A. (1985), "Growth rate and life span in Drosophila V. The effect of prolongation of the period of growth on the total duration of life (J.H. Northrop, 1917) – revisited", Mech. Ageing Dev., vol. 33, no. 1 (published December 1985), pp. 103–113, doi:10.1016/0047-6374(85)90112-5, PMID 3908838, S2CID 23576391 Herriott, R. M. (1981), "John Howard Northrop", J. Gen. Physiol., vol. 77, no. 6 (published June 1981), pp. 597–599, doi:10.1085/jgp.77.6.597, PMC 2215443, PMID 7021760 Herriott, R. M. (1994), "John Howard Northrop: July 5, 1891 – May 27, 1987", Biographical Memoirs. National Academy of Sciences (U.S.), vol. 63, pp. 423–450, PMID 11615389 See also this version of Northrop's National Academy of Science biography. Northrop, J. H. (1939), Crystalline Enzymes, Columbia University Press Shampo, M A; Kyle, R. A. (2000), "John Northrop – definitive study of enzymes", Mayo Clin. Proc., vol. 75, no. 3 (published March 2000), p. 254, doi:10.4065/75.3.254, PMID 10725951 van Helvoort, T. (1992), "The controversy between John H. Northrop and Max Delbrück on the formation of bacteriophage: bacterial synthesis or autonomous multiplication?", Annals of Science, vol. 49, no. 6 (published November 1992), pp. 545–575, doi:10.1080/00033799200200451, PMID 11616207

External links Works by or about John Howard Northrop at the Internet Archive John Howard Northrop on Nobelprize.org including the Nobel Lecture on December 12, 1946 The Preparation of Pure Enzymes and Virus Proteins

Illustrations

Worked examples

Example 1 — a first encounter with John Howard Northrop

Start with the simplest possible case. Write down what John Howard Northrop claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to John Howard Northrop before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about John Howard Northrop ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of John Howard Northrop

In research: John Howard Northrop appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses John Howard Northrop in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: John Howard Northrop is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1891 births, 1987 deaths, 1987 suicides, so understanding it makes those chapters shorter.
In everyday life: Look for John Howard Northrop outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study John Howard Northrop in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what John Howard Northrop means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain John Howard Northrop out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is John Howard Northrop in simple terms?

Why does John Howard Northrop matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study John Howard Northrop?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on John Howard Northrop.