Biographical Memoirs Volume 57 (1987) / Chapter Skim
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Gerhard Schmidt
Gerhard Schmidt
Pages 398-429
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From page 399... ...
In that same year, he accepted a postgraduate research fellowship in the biochemistry department there, the first step in a career progression that brought him eventually to the position of Privatdozent in the school's Department of Pathology. But Schmidt's career—like those of so many other scholars of Jewish extraction was suddenly interrupter!
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From page 400... ...
for evaluation, the crystals were supposedly iclentical to the adenylic acid that Levene and his group tract isolated from yeast nucleic acid by alkaline hydrolysis. A few months later, however, Schmidt was to revise this view profoundly.
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From page 401... ...
To reinforce his new finclings, he designed the following control. Since Levene's yeast aclenylic acid was obtained by subjecting yeast nucleic acid to a prolonged alkaline hydrolysis, Schmidt subjected muscle adenylic acid to the same type of hydrolysis.
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From page 402... ...
Because inosinic acid, the deamination product of muscle aclenylic acid, had been iclentifiect by Levene as a 5' nucleoticJe, muscle adenylic acid had to be consiclerect a 5' nucleoticle. Conversely, yeast adenylic acicI, which is now known to be simply an artifact of the alkaline degraciation, had to be assignee]
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From page 403... ...
to have rescuer! other Jewish medical scholars; apparently, however, Gustav Embclen was not one of them.
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From page 404... ...
In 1935 Schmidt obtained a Carnegie Foundation research fellowship for displaced German scholars. With it came his first chance to visit the Western Hemisphere, where he was invited to set up his own research program in the
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From page 405... ...
incubated with this enzyme releasecI the main part of the phosphorus of the nucleic acid; in contrast, upon enzymic incubation, nucleohistone releaser] only 20 percent of its phosphorus, presumably from the fraction corresponding to the free nucleic acicI.
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From page 406... ...
The heat-stable pancreas enzyme preparation did in fact catalyze a graclual depolymerization of yeast nucleic acicI, yielcling fractions that were still unable to pass through a cellophane membrane. They termed the digestion product "tetranucleoticles of high molecular weight." During this period, Levene held the firm belief that nucleic acids were polymers of tetranucleoticles, containing the four clifferent bases (two purines, two pyrimidines)
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From page 407... ...
The Coris tract founct that muscle adenylic acid was neeclecI for the enzymatic action of muscle phosphorylase. Schmidt was familiar with several purification techniques, some of which he had used in 1928 for the fractionation of muscle adenylic cleaminase; the cleaminase was used for the determination of adenylic acid.
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From page 408... ...
Despite these successes, Gerhard Schmidt was still in search of a permanent scientific home, and in the spring of 1940 he founc! one at the Tufts University Medical Center.
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From page 409... ...
During his almost forty years of research at the Tufts Mectical Center, Gerharct Schmidt chiefly explored two broact biochemical fields, both dealing with phosphorus compounds: nucleic acids anct phospholipicis. He adciressecl himself to both disciplines during his early years at Tufts, as well as during his later years.
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From page 410... ...
Schmidt's familiarity with pentose color reactions from his work on purine nucleotides was not of help for the new task; as he himself emphasized, pyrimidine nucleotides are too acid resistant in terms of releasing pentose and deoxyribose is destroyed during the protracted acid hydrolysis needed for release. Schmidt therefore designed a new method for nucleic acid analysis around the determination of phosphorus.
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From page 411... ...
Yeast ribonucleic acid was first treated with crystalline ribonuclease, which they prepared themselves; but this procedure clid not release any inorganic phosphate. Subsequently, a powerful "acid!
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From page 412... ...
These results spelled the enct of the era of the tetranucleoticle hypothesis anct paved the way for concepts that couIcl be emancipated from the earlier symmetry moclel. Also in 1946, Schmidt and coworkers studying phosphate uptake in bakers yeast anct the accumulation of phosphoric esters founcT an acicI-hycirolyzable fraction that was precipitable with barium acetate.
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From page 413... ...
When he returned later to the nucleic acid field, he revived his early interest in thymus nucleohistone. In a 1972 stucly of the amount of binding of divalent ions Ca+ + and Mg+ + to the phosphoric ester groups of thymus nucleohistones, Schmidt et al.
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From page 414... ...
, alternating with histone-free segments along the DNA chain; only the histone-free segments can binct divalent ions ant! are susceptible to DNAase, releasing acicI-soluble oligonucleoticles.
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From page 415... ...
C Joseph, described his studies of the composition of cerebral lipids in murine sudanophilic leucodystrophy.
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From page 416... ...
In addition to his research responsibilities, Schmidt taught at the Tufts Medical School, and this cluty he not only fulfilled but greatly treasured. His lectures for first-year mectical school biochemistry students covered structural macromolecules, preferably proteins and nucleic acids.
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From page 417... ...
His warm humor shone through, especially in his happy family circles but also among his friends. He could and often did make fun of his own absentmindedness.
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From page 418... ...
with me. This project, which involvect a return to the study of thymus nucleohistones, was very close to his heart.
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From page 419... ...
Volume 100 of Colowick and Kaplan's Methods in Enzymology is dedicated to the memory of Gerhard Schmidt as a scholar and artist; it inclucles a photograph of him playing his belovecT cello anct a charming little dedication by Sidney Colowick ancT Nathan Kaplan. In 198 I, the president of Tufts University establishect an annual Gerharct Schmidt lectureship commemorating Schmicit's long anct distinguishecT service to the Tufts University School of Medicine.
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From page 420... ...
1933-1934 Research Fellow, Department of Biochemistry, Uni versity of Stockholm, Sweden 1934-1935 Research Fellow, Department of General Pathology, University of Florence, Italy 1935-1937 Carnegie Foundation Research Fellowship for Dis placed German Scholars, Department of Chem istry, Queens University, Kingston, Ontario, Can ada 1937-1938 Assistant, Research Laboratory of Chemistry, Rocke feller Institute for Medical Research 1938 - 1940 Research Fellow, Department of Pharmacology, Washington University School of Medicine, St. Louis, Missouri
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From page 421... ...
GERHARD SCHMIDT 421 1940-1948 Research Associate, Thannhauser Research Labora tory, Boston Dispensary, Tufts University School of Medicine 1948-1955 Research Professor of Biochemistry, Department of Biochemistry, Tufts University School of Medicine 1955 - 1972 Professor of Biochemistry, Department of Biochem istry, Tufts University School of Medicine 1972-1981 Professor Emeritus of Biochemistry and Research Biochemist, Department of Biochemistry and Pharmacology, Tufts University School of Medi clne
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From page 422... ...
Chem., 197:191-92. Uber die Abbau des Guaninkerns durch die Fermente der Kaninchenleber.
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From page 423... ...
Enzymic depolymerization of deoxyribonucleic acids of different degrees of polymerization.
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From page 424... ...
Action of prostate phosphatase on yeast ribonucleic acid. Cold Spring Harbor Symp.
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From page 425... ...
Nature of the products formed by the action of crystalline ribonuclease on yeast ribonucleic acid.
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From page 426... ...
. In: The Nucleic Acids, vol.
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From page 427... ...
671-79; Preparation of ribonucleic acid from yeast and animal tissues, pp. 687-91; Chemical and enzymatic methods for the identification and structural elucidation of nucleic acids and nucleotides, pp.
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From page 428... ...
Okabe (from the Thannhauser Research Laboratory, Tufts University School of Medicine, Director: G Schmidt)
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From page 429... ...
The action of pancreas deoxyribonuclease I (deoxyribonucleate oligonucleotidohydrolase, EC-number 3.1.4.5.) on calf thymus nucleohistone.
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