Simultaneous isolation and determination of prothymosin α, parathymosin α, thymosin β4, and thymosin β10

Haritos, A.A.; Caldarella, Janet; Horecker, B.L.

doi:10.1016/0003-2697(85)90138-1

Cited by 29 publications

(15 citation statements)

References 9 publications

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“…Bovine and rat prothymosins a were isolated from thymus glands (11). Thymosin P4 was purified from rat thymus (12). Horse heart cytochrome c was from Schwarz/Mann.…”

mentioning

confidence: 99%

Sequencing of peptides and proteins with blocked N-terminal amino acids: N-acetylserine or N-acetylthreonine.

Wellner

Panneerselvam

Horecker

1990

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

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Many proteins cannot be directly sequenced by Edman degradation because they have a blocked N-terminal residue. A method is presented for deblocking such proteins when the N-terminal residue is N-acetylserine (which occurs frequently in eukaryotic proteins) or N-acetylthreonine. The method has been applied successfully to the determination of the N-terminal amino acid sequence of human, bovine, and rat parathymosins. Prothymosin a and other blocked proteins and peptides were also readily deblocked and sequenced by this procedure. It is proposed that the mechanism ofthe deblocking reaction involves an acid-catalyzed N -0 shift of the acetyl group followed by a fl-elimination.Although notable improvements have been made recently in the instrumentation' available for automated sequencing of proteins and peptides, many proteins still present a challenging problem to investigators who attempt to determine their sequence. One problem frequently encountered is that the N-terminal residue is modified in such a way that it does not react with the Edman reagent phenyl isothiocyanate. For

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“…Bovine and rat prothymosins a were isolated from thymus glands (11). Thymosin P4 was purified from rat thymus (12). Horse heart cytochrome c was from Schwarz/Mann.…”

mentioning

confidence: 99%

Sequencing of peptides and proteins with blocked N-terminal amino acids: N-acetylserine or N-acetylthreonine.

Wellner

Panneerselvam

Horecker

1990

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

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“…Peptide fragment thymosin t4 (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15) and the analog [Tyr12]-thymosin t4 (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15) were prepared by solid phase synthesis on an automatic Synostat-peptide synthesizer (Biotronik, Maintal, Germany) using 4-(hydroxymethyl)-phenoxymethyl-copoly-(styrene-1% divinyl-benzene)-resin preloaded with FMOC-Ser (tBu)-OH (for each synthesis 0.33 g = 0.26 mmol). The synthetic analog [TyrlZ]-thymosin /34 (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15) was radioiodinated by the chloramine T method as previously reported for tracers prepared for e-thymosin radioimmunoassays 15'16. All amino acids were coupled twice in DMF in threefold excess in the presence of 0.35 g BOP/0.11 g HOBt and 1.6 ml diisopropylethylamine (25% in DMF).…”

Section: Methodsmentioning

confidence: 99%

Evidence for the extranuclear localization of thymosins in thymus

et al. 1992

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A new radioimmunoassay has been developed for thymosin beta 4 by generating rabbit polyclonal antibodies against the synthetic N-terminal peptide fragment 1-15 coupled to KLH. The synthetic analogue [Tyr12]-thymosin beta 4 (1-15) was used as tracer. This radioimmunoassay, with a useful range of 10-1000 pmoles, showed cross-reactivity with the second homologous beta-thymosin of man and rat (thymosin beta 10) but not of calf (thymosin beta 9). This radioimmunoassay, together with an improved radioimmunoassay for the N-terminus of parathymosin alpha, was employed for the measurement of the levels of thymosin beta 4 and parathymosin alpha in nuclear and extranuclear extracts of calf thymus. The bulk of these polypeptides was found in the extranuclear material whereas only traces were observed in the nuclear environment, which indicates the extranuclear localisation of alpha- and beta-thymosins.

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“…Since the sedimentation equilibrium experiments were carried out at a high concentration -7 mg/ml or 2.2 mM of thymosin Crl -the peptide should be monomeric at the low concentrations that occur in vivo; for example, prothymosin ~ is present at a concentration of 400/zg/g or 0.03 mM in the rat thymus [28].…”

Section: Resultsmentioning

confidence: 99%

On the molecular size of thymosins

Haritos¹,

Yialouris²,

Heimer³

et al. 1987

FEBS Letters

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The immunoregulatory polypeptide prothymosin alpha and its biologically active N-terminal fragment thymosin alpha 1m, with relative molecular masses of 12,500 and 3108 respectively, were found to behave as oligomers (trimers to hexamers) in gel-filtration measurements. This phenomenon of an apparent association of polypeptides has been reported for other thymosins--parathymosin alpha, thymosin beta 4 and thymosin beta 10. In contrast, sedimentation equilibrium ultracentrifugation shows that thymosin alpha 1 is a monomer with a relative molecular mass of 3000 +/- 200. Measurement of the diffusion coefficient as 221 micron2/s suggests that the molecule is approximately spherical. The implications for the molecular species of prothymosin alpha, parathymosin alpha, and beta-thymosins are discussed.

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Simultaneous isolation and determination of prothymosin α, parathymosin α, thymosin β4, and thymosin β10

Cited by 29 publications

References 9 publications

Sequencing of peptides and proteins with blocked N-terminal amino acids: N-acetylserine or N-acetylthreonine.

Sequencing of peptides and proteins with blocked N-terminal amino acids: N-acetylserine or N-acetylthreonine.

Evidence for the extranuclear localization of thymosins in thymus

On the molecular size of thymosins

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