Role of the tryptophan residue in the interaction of pancreozymin with its receptor

Rajh, Hubertus M.; Smyth, Maria; Renckens, Bernadet; Jansen, J.W.C.M.; Pont, J.J.H.H.M. de; Bonting, S.L.; Tesser, G. I.; Nivard, R. J. F.

doi:10.1016/0304-4165(80)90234-2

Cited by 14 publications

(2 citation statements)

References 26 publications

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“…Despite suggestions that the Trp30 residue is important for intramolecular interactions to confer stable structure to CCK (Adachi et al, 1981), previous structure-activity studies of the Trp30 residue of CCK suggest that certain modifications can be introduced into this residue in the middle of the receptor-binding domain without dramatic loss of binding or biological activities (Adachi et al, 1981;Penke et al, 1984;Rajh et al, 1980). Replacement of the hydrogens in position 5 or 6 of the indole ring of Trp30 with fluorine does not alter the potency of these CCK analogues to stimulate pancreatic enzyme secretion (Rajh et al, 1980). Also, methylation of the Trp30 indole nitrogen has been reported to lower potency of this analogue only by a factor of 30 (Adachi et al, 1981).…”

Section: Discussionmentioning

confidence: 99%

Use of a nitrotryptophan-containing peptide for photoaffinity labeling the pancreatic cholecystokinin receptor

et al. 1989

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We report the preparation and characterization of a new type of intrinsic photoaffinity labeling probe, on the basis of the incorporation of a photolabile nitrotryptophan into a biologically relevant domain of a peptide. The model system used was the pancreatic cholecystokinin (CCK) receptor, previously affinity labeled with a variety of probes. Those studies have suggested that an Mr = 85,000-95,000 protein is more likely to be labeled as the site of covalent attachment approaches the receptor-binding domain of this hormone. Indeed, CCK has a Trp in the center of its receptor-binding region, and replacement of that residue with 6-nitrotryptophan resulted in a photolabile probe which affinity labeled the same Mr = 85,000-95,000 pancreatic membrane protein. This probe, 125I-D-Tyr-Gly-[(Nle28,31,6-NO2-Trp30)CCK-26-33], was synthesized by solid-phase and solution techniques and characterized by mass spectrometry. Following oxidative iodination, it was purified on HPLC to 2000 Ci/mmol. Binding to pancreatic membranes was rapid, temperature dependent, reversible, saturable, and specific and was with high affinity (Kd = 3 nM). While its binding affinity was only 3-fold lower than that of native CCK-8, this probe was 70-fold less potent than native hormone in stimulating amylase secretion (EC50 = 1 nM) and equally efficacious to native hormone. Despite the slight decrease in affinity, this probe demonstrated a high relative efficiency of covalent labeling of the Mr = 85,000-95,000 protein. This confirms that the Mr = 85,000-95,000 protein represents the hormone-binding subunit of the CCK receptor and demonstrates the utility of this type of photoaffinity labeling probe.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Discussionmentioning

confidence: 99%

Use of a nitrotryptophan-containing peptide for photoaffinity labeling the pancreatic cholecystokinin receptor

et al. 1989

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“…To date we do not know whether our fractions contain the same tryptophan-rich protein as that described by this author. Tryptophan in proteins seems to be essential for their biological activity (Rajh et al, 1980). It appears that red light is less destructive for some pineal substances.…”

Section: Results With Ultrafiltrated Pineal Fractions Prepared Witmentioning

confidence: 99%

The effect of ovine pineal compounds prepared under red or green light on the activity of male rat anterior pituitariesin vitro

Slama-Scemama

Noteborn

Moreé

et al. 1985

J. Neural Transmission

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A high molecular weight fraction XM100R (MW A 100,000) was prepared by ultrafiltration from ovine pineals using two different extraction methods under red light conditions (lambda greater than 600 nm). This fraction stimulates the release of radioimmunologically active luteinizing hormone (LH) of anterior pituitaries in vitro. The ultrafiltration fraction PM30R (MW greater than 30,000 and less than 100,000) was found to be radioimmunologically active only when the "Bensinger" extraction procedure was applied. However, when comparable fractions were prepared under green light and incubated with half-pituitaries, all the incubation media of the ultrafiltrated fractions, XM100R, PM30R, PM10R (MW greater than 10,000 and less than 30,000) UM2R (MW greater than 1000 and less than 10,000), UM05R (MW greater than 500 and less than 1000) and UM05F (MW greater than 500), reacted with anti-LH. This may mean that under green light conditions the high molecular weight ovine pineal compounds in XM100R are disintegrated and/or split up into small molecules which can stimulate the release of LH, or crossreact with the anti-LH serum.

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Peptidic and Proteic Substances Isolated from Pineals and Their Relation to the Hypophysial-Hypothalamic-Gonadal Axis

Ebels

1983

The Pineal Gland and Its Endocrine Role

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Role of the tryptophan residue in the interaction of pancreozymin with its receptor

Cited by 14 publications

References 26 publications

Use of a nitrotryptophan-containing peptide for photoaffinity labeling the pancreatic cholecystokinin receptor

Use of a nitrotryptophan-containing peptide for photoaffinity labeling the pancreatic cholecystokinin receptor

The effect of ovine pineal compounds prepared under red or green light on the activity of male rat anterior pituitariesin vitro

Peptidic and Proteic Substances Isolated from Pineals and Their Relation to the Hypophysial-Hypothalamic-Gonadal Axis

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