Insulin Crystals. I. The Minimum Mole-Fraction of Metal in Insulin Crystals Prepared with Zn++, Cd++, Co++, Ni++, Cu++, Mn++, or Fe++.

Schlichtkrull, J.; Årtun, Torstein; Waterman, H. I.; Eliasson, N. A.; Thorell, B.

doi:10.3891/acta.chem.scand.10-1455

Cited by 89 publications

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“…At pH 7-8, zinc and other divalent metal ions (e.g., Co2+, Cd2+, Ni2+, Mn2+, and Fe2+) strongly shift the equilibrium toward the higher aggregation state(s). When the [Zn]/[In]' ratio is 60.33, the hexameric state predominates; at higher ratios, there is a pronounced tendency to form higher aggregates and to crystallize or precipitate (Cunningham et al, 1955;Schlichtkrull, Fredericq, 1956;Grant et al, 1972;Jeffrey, 1974;Goldman & Carpenter, 1974;Milthorpe et al, 1977). Earlier work from this laboratory (Dunn et al, 1980) has shown that, in mixtures of zinc and insulin with a [Zn2+]/[In] ratio below 0.33, the reactivity of the zinc ions toward a large excess of the tridentate chelator 2,2',2"-terpyridine (terpy) is indeed consistent with the assignment of the metal ion environment to that of the crystallographically identified His-B 10 sites.…”

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confidence: 90%

Effects of calcium ion on ternary complexes formed between 4-(2-pyridylazo)resorcinol and the two-zinc insulin hexamer

Kaarsholm¹,

Dunn²

1987

Biochemistry

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As a means for probing the microenvironment of zinc in the insulin hexamer and to investigate the effects of calcium ion on the assembly and the structure of the two-zinc insulin hexamer, the thermodynamics and kinetics of the reaction between the chromophoric divalent metal ion chelator 4-(2-pyridylazo)resorcinol (PAR) and zinc-insulin have been investigated over a wide range of conditions. For [PAR]0 much greater than [Zn2+]0 and [Zn2+]/[In] less than or equal to 0.33, the reaction leads to the sequestering and ultimate removal of all of the insulin-bound Zn2+; for [Zn2+]0 much greater than [PAR]0, two stable ternary complexes are formed where Zn2+ has ligands derived from PAR as well as from hexameric insulin. For [Zn2+]/[In] ratios below 0.33, the equilibrium distribution between the two ternary complexes is dependent on the [Zn2+]/[In] ratio. One of the complexes is assigned to the monoanion of PAR coordinated to Zn2+ that resides in a His-B10 site. The other complex is proposed to involve the coordination of (PAR)Zn to the site formed by the alpha-NH2 group of Phe-B1 and the gamma-carboxylate ion of Glu-A17 across the dimer-dimer interface on the surface of the hexamer. With either PAR or zinc-insulin in large excess, the kinetics of the PAR optical density changes are remarkably similar and biphasic. The faster step is first order in PAR and first order in insulin-bound Zn2+ (k congruent to 3 X 10(3) M-1 s-1) and involves the formation of an intermediate in which PAR is coordinated to insulin-bound zinc at the His-B10 site.(ABSTRACT TRUNCATED AT 250 WORDS)

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confidence: 90%

Effects of calcium ion on ternary complexes formed between 4-(2-pyridylazo)resorcinol and the two-zinc insulin hexamer

Kaarsholm¹,

Dunn²

1987

Biochemistry

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“…The insulin in this material was purified to homogeneity by HPLC (18). Zinc insulin crystals were prepared using standard procedures (19).…”

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confidence: 99%

Sequence of a New World primate insulin having low biological potency and immunoreactivity.

Seino

Steiner

Bell

1987

Proc. Natl. Acad. Sci. U.S.A.

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“…2), very similar to those of native insulin, were grown from citrate buffer as described by Schlichtkrulll 18 1 for the preparation of 2 Zn insulin. Following the addition of ZnSO4> sodium citrate and acetone, 0.02M HC1 was added dropwise until a permanent turbidity formed in the crystallizing solution.…”

Section: Crystallizationmentioning

confidence: 99%

Preparation of a Crystalline A1-(2-Nitro-4-trimethylammoniophenyl) Derivative of Bovine Insulin

Sutton¹,

Easter²,

Drewes³

1976

Hoppe-Seyler´s Zeitschrift für physiologische Chemie

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The reaction of bovine insulin with the hydrophilic reagent l-fluoro-2-nitro-4-trimethylammoniobenzene iodide at pH 8.2 has been reexamined. From the mixture of products a crystalline derivative substituted at the Gly A1 terminus has been isolated. It has been characterized by amino acid analysis, end group analysis, cellulose acetate electrophoresis and sulphitolysis. The derivative has a biological activity (mouse convulsion assay) of 60% relative to insulin. Darstellung von kristallinem Al-(2-Nitro-4-trimethylammoniophenyl)-RinderinsulinZusammenfassung: Rinderinsulin wurde mit l-Fluor-2-nitro-4-trimethylammoniobenzol-jodid umgesetzt; als Hauptprodukt wurde ein kristallines Derivat isoliert, das ein amN-terminalen Glycin der -Kette substituiertes Insulin darstellt. Die biologische Aktivität im Mauskrampftest beträgt 60% verglichen mit Insulin.

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Insulin Crystals. I. The Minimum Mole-Fraction of Metal in Insulin Crystals Prepared with Zn++, Cd++, Co++, Ni++, Cu++, Mn++, or Fe++.

Cited by 89 publications

References 0 publications

Effects of calcium ion on ternary complexes formed between 4-(2-pyridylazo)resorcinol and the two-zinc insulin hexamer

Effects of calcium ion on ternary complexes formed between 4-(2-pyridylazo)resorcinol and the two-zinc insulin hexamer

Sequence of a New World primate insulin having low biological potency and immunoreactivity.

Preparation of a Crystalline A1-(2-Nitro-4-trimethylammoniophenyl) Derivative of Bovine Insulin

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