The destructive action of heat on insulin solutions

Krogh, August; Hemmingsen, Axel M.

doi:10.1042/bj0221231

Cited by 20 publications

(13 citation statements)

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“…5 The precipitate was shown to be insoluble in acid but to resume its original solubility and activity in dilute alkali. 3,6,7 The first systematic study of the heat precipitation of insulin was published by Krogh and Hemmingsen, 4 who found the rate of inactivation at pH 3 to be proportional to the insulin concentration and to closely follow the law of Arrhenius in the temperature interval 50-117°C. Subsequent studies showed the rate of reaction in acid to increase with acidity in the pH range from 3 to 1 and to be dependent of the type of acid (H 2 SO 4 > HCl > H 3 PO 4 .…”

Section: Introductionmentioning

confidence: 99%

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Toward Understanding Insulin Fibrillation

Brange

Andersen

Laursen

et al. 1997

Journal of Pharmaceutical Sciences

480

525

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Formation of insulin fibrils is a physical process by which partially unfolded insulin molecules interact with each other to form linear aggregates. Shielding of hydrophobic domains is the main driving force for this process, but formation of intermolecular beta-sheet may further stabilize the fibrillar structure. Conformational displacement of the B-chain C-terminal with exposure of nonpolar, aliphatic core residues, including A2, A3, B11, and B15, plays a crucial role in the fibrillation process. Recent crystal analyses and molecular modeling studies have suggested that when insulin fibrillates this exposed domain interacts with a hydrophobic surface domain formed by the aliphatic residues A13, B6, B14, B17, and B18, normally buried when three insulin dimers form a hexamer. In rabbit immunization experiments, insulin fibrils did not elicit an increased immune response with respect to formation of IgG insulin antibodies when compared with native insulin. In contrast, the IgE response increased with increasing content of insulin in fibrillar form. Strategies and practical approaches to prevent insulin from forming fibrils are reviewed. Stabilization of the insulin hexameric structure and blockage of hydrophobic interfaces by addition of surfactants are the most effective means of counteracting insulin fibrillation.

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Section: Introductionmentioning

confidence: 99%

“…[2][3][4] The phenomenon was termed heat denaturation or coagulation, but it was shown later that heat precipitation and insulin fibrillation are directly related. 5 The precipitate was shown to be insoluble in acid but to resume its original solubility and activity in dilute alkali.…”

Section: Introductionmentioning

confidence: 99%

Toward Understanding Insulin Fibrillation

Brange

Andersen

Laursen

et al. 1997

Journal of Pharmaceutical Sciences

480

525

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“…Since the constants computed for different time intervals show such good agreement, the assumption that the degradation of crystalline insulin is a monomolecular reaction, at least at 37~ receives confirmation. First order kinetics for insulin degradation in solution have earlier been described [1,7].…”

Section: Discussionmentioning

confidence: 99%

“…Earlier studies [1][2][3][4][5][6][7], have investigated the stability of insulin in solution or suspension. This report describes the stability of crystalline insulin.…”

mentioning

confidence: 99%

Stability of the 4th International Standard for Insulin

et al. 1975

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Summary. The stability of the (W.H.O.) 4th InternationalStandard for Insulin, has been assessed by accelerated thermal degradation studies. This is a crystalline preparation of insulin, freed from proteolytic enzymes, sealed in ampoules containing air and with a moisture content of 5-6%. Of the original biological activity 95.8 (92.8-98.9; P = 0.95)% was retained after storage for 12 years in the dark at 20 ~ C and 65.7 (63.4-68.1; P= 0.95)% after 14 years at 37 ~ C. Degradation rate constants were calculated from these data for the Standard at 20 ~ C and 37 ~ C, assuming first order kinetics. The degradation constant at 37~ did not differ significantly from those found in earlier degradation studies at 37~ over shorter periods, thereby supporting the assumption that the degradation of crystalline insulin, at least at 37 ~ C, is a first order reaction. Extrapolation of these data suggests that the Standard stored at -20~ for 20 years would have retained at least 99.93% (P = 0.95) of its original activity and so for practical purposes can be considered to be stable.

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“…The inherent tendency of insulin to undergo conformational changes resulting in aggregation and formation of a viscous gel or insoluble precipitates was observed early in the insulin era (du Vigneaud et al, 1928;Krogh and Hemmingsen, 1928). This so-called fibrillation of insulin undoubtedly caused the early period 's low yields in extraction of insulin from the pancreas, and later on , hampered the development of chromatographically purified insulin (Schlichtkrull et al.…”

Section: Fibrillationmentioning

confidence: 99%