Reaction of silk fibroin with diazomethane

Rutherford, Henry A.; Patterson, Wilbur I.; Harris, Milton

doi:10.6028/jres.025.014

Cited by 19 publications

(9 citation statements)

References 9 publications

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“…This result is not unexpected, as Rutherford, Patterson, and Harris [5] concluded, on the basis of their study of the methylation of fibroin with diazomethane, that the hydroxyl groups are free. The greatest amount of base bound in the range covered by this investigation, 0.90 M-eqjg, is somewhat more than the tyrosine alone would account for and is, fortuitously, equal to the tyrosine content plus the estimated content of free carboxyl groups.…”

Section: Harrismentioning

confidence: 53%

“…(b) METHYLATED FIBROIN Fibroin was methylated with diazomethane as described by Rutherford, Patterson, and Harris [5] . Analysis of the samples for tyrosine by the method of Lugg [7] showed that the tyrosine content…”

Section: Methodsmentioning

confidence: 99%

“…The total amount of acid plus base bound between pH 1 and pH 7 to 8 (in which range the -OOOH groups are known to undergo dissociation), which is not less than 0.13 and may be as much as 0.17 M-eqjg in the case of silk fibroin, may be regarded as a measure of the total number of free carboxyl groups in the protein. Previous evidence that silk fibroin contains free carboxyl groups was given by Rutherford, Patterson, and Harris [5], who infer the presence of about 0.2 M-eqjg of free carboxyl groups in the untreated ' ,fibroin from the analyses of methylated fibroin for unmethylated tyrosine and for methoxyl groups. The latter estimate lends support to the interpretation of the quantity of acid plus base bound between pH 1 and 8 as representing the free carboxyl content of fibroin.…”

Section: Harrismentioning

confidence: 99%

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Combination of silk fibroin with acid and with base

Gleysteen¹,

Harris²

1941

J. RES. NATL. BUR. STAN.

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A study was made of the dependence on pH of the amounts of hydrochloric acid and of potassium hydroxide that are taken up by silk fibroin at 0° C. The effect of added potassium chloride on this dependence was also investigated, and was shown to be the binding of an increased quantity of acid or base at a given pH.The maximum acid-combining capacity of silk fibroin is 0.13 milliequivalent per gram; the maximum base-binding capacity is greater than 0.90 milliequivalent per gram. The presence of 0.13 to 0.17 milliequivalent of free carboxyl groups in silk fibroin is estimated from the titration curve. The great amount of base bound can be accounted for only if the phenolic hydroxyl groups of tyrosine take part in the equilibria with base. Further evidence that these groups bind base is provided by the greatly decreased amount of base bound by methylated fibroin. CONTENTS Page

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Section: Harrismentioning

confidence: 53%

Section: Methodsmentioning

confidence: 99%

Section: Harrismentioning

confidence: 99%

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Combination of silk fibroin with acid and with base

Gleysteen¹,

Harris²

1941

J. RES. NATL. BUR. STAN.

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“…M ethylated samples were prepared using diazomethane according to the procedure recently described by Rutherford, Patterson, and Harris [7]. The acidic groups of degummed and of electro dialyzed silk have different rates of reaction with diazomethane, and it was possible to methylate an approximate, predetermined fraction of the carboxylic acid and tyrosine hydroxyl groups.…”

Section: Experimental Procedures 1 Materialsmentioning

confidence: 99%

“…The acidic groups of degummed and of electro dialyzed silk have different rates of reaction with diazomethane, and it was possible to methylate an approximate, predetermined fraction of the carboxylic acid and tyrosine hydroxyl groups. The extent of methylation of each of these groups was directly determined by the procedure previously described [7]. The decrease in tyrosine content is a measure of the hydroxyl groups methylated.…”

Section: Experimental Procedures 1 Materialsmentioning

confidence: 99%

Photochemical reactions in silk

Rutherford¹,

Harris²

1941

J. RES. NATL. BUR. STAN.

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The stability of silk to light, appears to be in part influenced by the cations in the silk . The removal of cationic subst, Rnces from silk by two independent methods results in practically identical decreases in the stability of the fib ers to light ; the introduction of cations by treat m ent with basic compounds appreciably increases the s ta bility .Me thylation of the carboxylic acid groups in silk by treatment with diazomethane does not appreciably change the photochemical behavior of the fiber, whereas methylation of only a small percentage of the hydroxyl groups of the tyrosine results in a marked increase in photochemical stability. The res ults suggest tha t alteration of the tyrosine hydroxyl groups by reaction with various reagents is responsible for a t least part of these stabilizing effects.

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Über Chemie und Feinbau von Naturseide

Spoor

Ziegler

1960

Angewandte Chemie

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Diese Ubersicht zeigt, welche neueren Kenntnisse in den letzten Jahren erhalten werden konnten. Nach einer Darlegung d e r mikroskopischen und rontgenographischen Befunde wird ausfuhrlicher auf die Chemie des Seidenfibroins eingegangen, wobei den Arninosaure-Sequenzen im kristallinen und amorphen Teil die besondere Aufrnerksarnkeit gilt. EinleitungWahrend Fasern aus synthetischen Polymeren nur aus einem oder zwei verschiedenen Bausteinen aufgebaut sind, werden tierische Fasern aus nahezu allen in der Natur vorkommenden Aminosauren gebildet und sind wegen der ungeheuer groBen Zahl der Verkniipfungsrnoglichkeiten recht kompliziert zusammengesetzt. Von der Wolle z. B. weiB man bis heute nicht einmal, aus wievielen Proteinen die Faser aufgebaut ist. Seide besteht morphologisch aus zwei relativ leicht isolierbaren Teilen, dem Sericin und dem faserbildenden Fibroin, die man rnit groBer Wahrscheinlichkeit als einheitliche Proteine ansprechen darf. Weil Fibroin im Gegensatz ZLI anderen Faserproteinen zu etwa 60% aus Glycin und Alanin besteht tind fast frei von schwefel-haltigen Aminosauren ist, eignet es sich vergleichsweise a m besten a k Modellstibstanz fur das Studium von Strukttir trnd Eigenschaften solcher Substanzen. Abb. 1 a und b. Elektronenmikroskopisches Bild von im Starmix zerkleinertem, unbehandeltem Fibroin: Fibrillen 100 bis 200 A breit (Platinbedampfung, urspriinglich x 30000); nach Zuber6S6) .~ I ) M . S. Dunn, M . N.

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Reaction of silk fibroin with diazomethane

Abstract: The treatment of silk with an ethereal solution of diazometbane resu lt ed in a rapid decrease in tyrosine content, with no appreciable d ecrease in tensile strength Show more

Cited by 19 publications

References 9 publications

Combination of silk fibroin with acid and with base

Combination of silk fibroin with acid and with base

Photochemical reactions in silk

Über Chemie und Feinbau von Naturseide

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