Esmond Emerson Snell (September 22, 1914 – December 9, 2003) was an American
biochemist
Biochemists are scientists who are trained in biochemistry. They study chemical processes and chemical transformations in living organisms. Biochemists study DNA, proteins and Cell (biology), cell parts. The word "biochemist" is a portmanteau of ...
who spent his career researching
vitamin
A vitamin is an organic molecule (or a set of molecules closely related chemically, i.e. vitamers) that is an Nutrient#Essential nutrients, essential micronutrient that an organism needs in small quantities for the proper functioning of its ...
s and nutritional requirements of bacteria and
yeast
Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are estimated to constitut ...
. He is well known for his study of
lactic acid
Lactic acid is an organic acid. It has a molecular formula . It is white in the solid state and it is miscible with water. When in the dissolved state, it forms a colorless solution. Production includes both artificial synthesis as well as natu ...
-producing bacteria, developing microbiological assays for a number of key
nutrient
A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi, and protists. Nutrients can be incorporated into cells for metabolic purposes or excret ...
s; the discovery of more than half of known vitamins has been attributed to the use of this work. He discovered several
B vitamin
B vitamins are a class of water-soluble vitamins that play important roles in Cell (biology), cell metabolism and synthesis of red blood cells. Though these vitamins share similar names (B1, B2, B3, etc.), they are chemically distinct compounds th ...
s, including
folic acid
Folate, also known as vitamin B9 and folacin, is one of the B vitamins. Manufactured folic acid, which is converted into folate by the body, is used as a dietary supplement and in food fortification as it is more stable during processing and ...
, and characterized the biochemistry of
vitamin B6
Vitamin B6 is one of the B vitamins, and thus an essential nutrient. The term refers to a group of six chemically similar compounds, i.e., "vitamers", which can be interconverted in biological systems. Its active form, pyridoxal 5′-phosphat ...
(also known as pyrixodal).
Early life and education
The fourth of five children, Snell was born in 1914 in
Salt Lake City
Salt Lake City (often shortened to Salt Lake and abbreviated as SLC) is the Capital (political), capital and List of cities and towns in Utah, most populous city of Utah, United States. It is the county seat, seat of Salt Lake County, Utah, Sal ...
, Utah to parents who met while serving as
Mormon missionaries
Missionaries of the Church of Jesus Christ of Latter-day Saints (LDS Church)—widely known as Mormon missionaries—are volunteer representatives of the church who engage variously in proselytizing, church service, humanitarian aid, and commu ...
. The family moved several times in Wyoming and Utah before settling in
Provo, Utah
Provo ( ) is the fourth-largest city in Utah, United States. It is south of Salt Lake City along the Wasatch Front. Provo is the largest city and county seat of Utah County and is home to Brigham Young University (BYU).
Provo lies between the ...
so that the children could attend
Brigham Young University
Brigham Young University (BYU, sometimes referred to colloquially as The Y) is a private research university in Provo, Utah. It was founded in 1875 by religious leader Brigham Young and is sponsored by the Church of Jesus Christ of Latter-day ...
. Snell became interested in chemistry during high school and went on to study chemistry at BYU; he also – "reluctantly", as he remembered later – studied secondary education as "insurance" against the unemployment of the
Great Depression
The Great Depression (19291939) was an economic shock that impacted most countries across the world. It was a period of economic depression that became evident after a major fall in stock prices in the United States. The economic contagio ...
.
After graduation, he received a scholarship to continue his studies at the
University of Wisconsin–Madison
A university () is an educational institution, institution of higher education, higher (or Tertiary education, tertiary) education and research which awards academic degrees in several Discipline (academia), academic disciplines. Universities ty ...
, where he joined the research group of
William Harold Peterson and began his long career studying nutrition and metabolism in microorganisms. Snell received his PhD in biochemistry in 1938 and moved to the
University of Texas at Austin
The University of Texas at Austin (UT Austin, UT, or Texas) is a public research university in Austin, Texas. It was founded in 1883 and is the oldest institution in the University of Texas System. With 40,916 undergraduate students, 11,075 ...
, where he worked as a
postdoctoral fellow
A postdoctoral fellow, postdoctoral researcher, or simply postdoc, is a person professionally conducting research after the completion of their doctoral studies (typically a PhD). The ultimate goal of a postdoctoral research position is to p ...
with
Roger J. Williams
Roger John Williams (August 14, 1893 – February 20, 1988), was an American biochemist. He is known for is work on vitamins and human nutrition. He had leading roles in the discovery of folic acid, pantothenic acid, vitamin B6, lipoic acid ...
.
Academic career
Snell began his independent research career with an appointment as an assistant professor of chemistry at the University of Texas at Austin in 1941, advancing to associate professor in 1943. He then moved back to his alma mater in 1945, joining the biochemistry faculty of the University of Wisconsin and remaining there until 1951, when he returned to Austin to occupy newly constructed laboratory space. In 1956 he was offered the chairmanship of the biochemistry department at the
University of California, Berkeley
The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California) is a public land-grant research university in Berkeley, California. Established in 1868 as the University of California, it is the state's first land-grant u ...
, and relocated his laboratory there. He served as chair until 1956 and remained in the department until 1976, departing briefly for
sabbatical
A sabbatical (from the Hebrew: (i.e., Sabbath); in Latin ; Greek: ) is a rest or break from work.
The concept of the sabbatical is based on the Biblical practice of ''shmita'' (sabbatical year), which is related to agriculture. According to ...
visits to
Feodor Lynen
Feodor Felix Konrad Lynen (; 6 April 19116 August 1979) was a German biochemist. In 1964 he won the Nobel Prize in Physiology or Medicine together with Konrad Bloch for their discoveries concerning the mechanism and regulation of cholesterol an ...
's research group in
Munich
Munich ( ; german: München ; bar, Minga ) is the capital and most populous city of the States of Germany, German state of Bavaria. With a population of 1,558,395 inhabitants as of 31 July 2020, it is the List of cities in Germany by popu ...
, Germany and later to
Osaka University
, abbreviated as , is a public research university located in Osaka Prefecture, Japan. It is one of Japan's former Imperial Universities and a Designated National University listed as a "Top Type" university in the Top Global University Project. ...
in 1971. After 20 years at Berkeley, Snell again returned to Austin for family reasons and became the chair of the microbiology department there for the following four years. Snell became the
Ashbel Smith
Ashbel Smith (August 13, 1805 – January 21, 1886) was a pioneer physician, diplomat, slave owner, and official of the Republic of Texas, Confederate officer and first President of the Board of Regents of the University of Texas. Smith was an a ...
Professor of Chemistry in 1980 and retired, assuming
professor emeritus
''Emeritus'' (; female: ''emerita'') is an adjective used to designate a retired chair, professor, pastor, bishop, pope, director, president, prime minister, rabbi, emperor, or other person who has been "permitted to retain as an honorary title ...
status, in 1990.
During his career Snell served on a number of
scientific journal
In academic publishing, a scientific journal is a periodical publication intended to further the progress of science, usually by reporting new research.
Content
Articles in scientific journals are mostly written by active scientists such as s ...
editorial boards, most notably as the editor of the ''
Annual Review of Biochemistry
''Annual Review of Biochemistry'' is an annual peer reviewed scientific journal published by Annual Reviews, a nonprofit scientific publisher. Its first volume was published in 1932, and its founding editor was J. Murray Luck. The current editor ...
'' from 1968 to 1983 and of ''
Biochemical and Biophysical Research Communications
''Biochemical and Biophysical Research Communications'' is a weekly peer-reviewed scientific journal covering all aspects of biochemistry and biophysics. It was established in 1959 by Academic Press and is currently published by Elsevier. The ed ...
'' from 1970 to 1985.
Research
Snell is widely recognized as one of the foremost nutritional biochemists of the 20th century. His early work developing microbiological assays for key nutrients has been credited with facilitating the discovery of at least half of known vitamins due to their ease of use compared to more traditional animal studies.
His 1939 publication describing a microbiological assay for
riboflavin
Riboflavin, also known as vitamin B2, is a vitamin found in food and sold as a dietary supplement. It is essential to the formation of two major coenzymes, flavin mononucleotide and flavin adenine dinucleotide. These coenzymes are involved in ...
– then one of just two
B vitamins
B vitamins are a class of water-soluble vitamins that play important roles in cell metabolism and synthesis of red blood cells. Though these vitamins share similar names (B1, B2, B3, etc.), they are chemically distinct compounds that often coexist ...
known – is considered the first widely used such assay.
His notable discoveries using these methods include the discovery and naming of
folic acid
Folate, also known as vitamin B9 and folacin, is one of the B vitamins. Manufactured folic acid, which is converted into folate by the body, is used as a dietary supplement and in food fortification as it is more stable during processing and ...
, which
Herschel K. Mitchell, Snell, and
Roger J. Williams
Roger John Williams (August 14, 1893 – February 20, 1988), was an American biochemist. He is known for is work on vitamins and human nutrition. He had leading roles in the discovery of folic acid, pantothenic acid, vitamin B6, lipoic acid ...
isolated from four tons of processed
spinach
Spinach (''Spinacia oleracea'') is a leafy green flowering plant native to central and western Asia. It is of the order Caryophyllales, family Amaranthaceae, subfamily Chenopodioideae. Its leaves are a common edible vegetable consumed either f ...
and demonstrated to be a
growth factor
A growth factor is a naturally occurring substance capable of stimulating cell proliferation, wound healing, and occasionally cellular differentiation. Usually it is a secreted protein or a steroid hormone. Growth factors are important for regu ...
for the experimental organism ''
Streptococcus faecalis
''Enterococcus faecalis'' – formerly classified as part of the group D ''Streptococcus'' system – is a Gram-positive, commensal bacterium inhabiting the gastrointestinal tracts of humans. Like other species in the genus ''Enterococcus'', ''E ...
''.
A version of Snell's microbiological assay method based on the experimental organism ''
Lactobacillus casei
''Lacticaseibacillus casei ''is an organism that belongs to the largest genus in the family ''Lactobacillaceae'', a lactic acid bacteria (LAB), that was previously classified as ''Lactobacillus casei-01''. This bacteria has been identified as facu ...
'' (now known as ''Lactobacillus rhamnosus'') is still used as a method for detecting folates in blood.
Snell's interest in isolating and characterizing unknown nutrients and growth factors also led to the serendipitous discovery of useful biochemical tools. While working to characterize the yeast growth factor that would become known as
biotin
Biotin (or vitamin B7) is one of the B vitamins. It is involved in a wide range of metabolic processes, both in humans and in other organisms, primarily related to the utilization of fats, carbohydrates, and amino acids. The name ''biotin'', bor ...
, Snell and coworkers discovered the egg white protein
avidin
Avidin is a tetrameric biotin-binding protein produced in the oviducts of birds, reptiles and amphibians and deposited in the whites of their eggs. Dimeric members of the avidin family are also found in some bacteria. In chicken egg white, avidin ...
, which binds biotin with extremely high affinity. At the time avidin was noted as a cause of "egg white injury", a form of biotin deficiency in animals.
The rarity and expense of obtaining biotin at the time limited further investigations, but the extremely high avidin-biotin binding affinity was later exploited and is now widely used in
molecular biology
Molecular biology is the branch of biology that seeks to understand the molecular basis of biological activity in and between cells, including biomolecular synthesis, modification, mechanisms, and interactions. The study of chemical and physi ...
for purification and molecular detection applications.
Snell is perhaps best known for his work on
vitamin B6
Vitamin B6 is one of the B vitamins, and thus an essential nutrient. The term refers to a group of six chemically similar compounds, i.e., "vitamers", which can be interconverted in biological systems. Its active form, pyridoxal 5′-phosphat ...
,
work he conducted at Texas with
Beverly Guirard
Beverly Marie Guirard was a microbiologist who worked on the biochemistry of microbial growth, especially with respect to vitamin B6. She is also known for her work defining the components of coenzyme A which was a part of the research that led to ...
, a long time associate in his lab.
He and Soviet scientist
Alexander E. Braunstein have been cited as the "fathers of vitamin B6".
Snell discovered two novel forms of the substance –
pyridoxal
Pyridoxal is one form of vitamin B6.
Some medically relevant bacteria, such as those in the genera ''Granulicatella'' and ''Abiotrophia'', require pyridoxal for growth. This nutritional requirement can lead to the culture phenomenon of satellit ...
and
pyridoxamine
Pyridoxamine is one form of vitamin B6. Chemically it is based on a pyridine ring structure, with hydroxyl, methyl, aminomethyl, and hydroxymethyl substituents. It differs from pyridoxine by the substituent at the 4-position. The hydroxyl at ...
– and thus elaborated the underlying biochemistry of
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
s that rely on pyridoxal
cofactors
Cofactor may also refer to:
* Cofactor (biochemistry), a substance that needs to be present in addition to an enzyme for a certain reaction to be catalysed
* A domain parameter in elliptic curve cryptography, defined as the ratio between the order ...
for catalysis. In a series of experiments beginning in the 1940s and later conducted with student
David Metzler, a general mechanism for the catalytic cycle of pyridoxal-dependent enzymes was discovered.
Recalling his own work with pyridoxal, French biophysicist
Michel E. Goldberg described Snell as "the pope of pyridoxal catalysis".
Awards and honors
Snell received a number of honors during his long career.
*
Eli Lilly Award in Bacteriology and Immunology (1945)
* Member,
National Academy of Sciences
The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Nati ...
(1955)
* Member,
American Academy of Arts and Sciences
The American Academy of Arts and Sciences (abbreviation: AAA&S) is one of the oldest learned societies in the United States. It was founded in 1780 during the American Revolution by John Adams, John Hancock, James Bowdoin, Andrew Oliver, and ...
(1962)
* Fellow,
American Institute of Nutrition (1982)
*
William C. Rose Award
The William C. Rose Award given by the American Society for Biochemistry and Molecular Biology recognizes outstanding contributions to biochemical and molecular biological research and a demonstrated commitment to the training of younger scientists ...
(1985)
In recognition of his contributions to the study of
vitamin B6
Vitamin B6 is one of the B vitamins, and thus an essential nutrient. The term refers to a group of six chemically similar compounds, i.e., "vitamers", which can be interconverted in biological systems. Its active form, pyridoxal 5′-phosphat ...
biochemistry, the 1999 meeting in a regular series of international symposia on pyridoxal catalysis was dedicated to Snell.
Personal life
While working at the University of Texas, Snell met his wife Mary, then a senior chemistry major. The couple married in 1941 and had four children, three sons and a daughter. They would return to the Austin, Texas area for family reasons twice during Snell's career. Mary died in 2003 after 62 years of marriage, while Snell died of
prostate cancer
Prostate cancer is cancer of the prostate. Prostate cancer is the second most common cancerous tumor worldwide and is the fifth leading cause of cancer-related mortality among men. The prostate is a gland in the male reproductive system that sur ...
and
congestive heart failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, a ...
at age 89, only six days after his wife's death. They were survived by three of their four children; one son was killed in action in 1968 during the
Vietnam War
The Vietnam War (also known by #Names, other names) was a conflict in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. It was the second of the Indochina Wars and was officially fought between North Vie ...
. The Snells were buried alongside their son in
El Cerrito, California
El Cerrito (Spanish for "The Little Hill") is a city in Contra Costa County, California, United States, and forms part of the San Francisco Bay Area. It has a population of 25,962 according to the 2020 census. El Cerrito was founded by refugees ...
.
References
{{DEFAULTSORT:Snell, Esmond Emerson
1914 births
2003 deaths
Scientists from Salt Lake City
American biochemists
University of Texas at Austin faculty
University of Wisconsin–Madison alumni
University of California, Berkeley faculty
Members of the United States National Academy of Sciences
Fellows of the American Academy of Arts and Sciences
Annual Reviews (publisher) editors