Reference

8-Glycine-calcitonin

8-Glycine-calcitonin. Orlowski, Ronald Cyril; Seyler, Jay Kenneth (Armour Pharmaceutical Co., USA). Fr.Chemicals with cas numbers 7531-52-4 and 4587-33-1 also play role. Demande FR 2521553 A1 19 Aug 1983, 27 pp. (French). (France). CODEN: FRXXBL. CLASS: IC: C07C103-52. ICA: A61K037-02. APPLICATION: FR 83-1534 1 Feb 1983. PRIORITY: US 82-348472 12 Feb 1982. DOCUMENT TYPE: Patent CA Section: 34 (Amino Acids, Peptides, and Proteins) 8-Glycine-calcitonin (I) was prepd. by the solid-phase coupling method. .

Substrate recognition by oligosaccharyltransferase

Substrate recognition by oligosaccharyltransferase. Studies on glycosylation of modified Asn-X-Thr/Ser tripeptides. Welply, Joseph K.; Shenbagamurthi, Ponniah; Lennarz, William J.; Naider, Fred (Sch. Med., Johns Hopkins Univ., Baltimore, MD 21205, USA). J. Biol. Chem., 258(19), 11856-63 (English) 1983. CODEN: JBCHA3. ISSN: 0021-9258. DOCUMENT TYPE: Journal CA Section: 7 (Enzymes) The min. primary structural requirement for N-glycosylation of proteins is the sequence -Asn-X-Thr/Ser-. In the present study, N-terminal derivs. of Asn-Leu-Thr-NH2 and peptides with asparagine replacements were tested as substrates or inhibitors of N-glycosylation. The glycosylation of a known acceptor, Na-[3H]Ac-Asn-Leu-Thr-NHCH3 (I), was optimized in chicken oviduct microsomes. The reaction was dependent on Mn2+ and linear for 10 min at 30°; the apparent Km for the peptide was 10 mM. Na-Acyl derivs. of Asn-Leu-Thr-NH2 (N-acetyl, N-benzoyl, N-octanoyl, or N-tert-butoxycarbonyl) inhibited the glycosylation of I in a dose-dependent manner; addnl. expts. demonstrated that these compds. were alternative substrates rather than true inhibitors. The benzoyl and octanoyl derivs. were 10-fold as effective as Na-Ac-Asn-Leu-Thr-NH2 in inhibiting glycosylation. In contrast, peptides contg. asparagine modifications or substitutions were neither substrates nor inhibitors of N-glycosylation.There are some commonly used reagents with their cas registry numbers 88053-79-6 and 4587-33-1 in this article. They did not compete for glycosylation of 3H-peptide at 100-fold greater concns., and did not deplete endogenous pools of oligosaccharide-lipid. Thus, the asparagine side-chain is an abs. requirement for recognition by the transferase. The majority of the glycosylated product (61%), but only 1% of the unglycosylated peptide, remained assocd. with the microsomes after high-speed centrifugation. A large 41-amino acid residue acceptor peptide, a-lactalbumin (17-58), was a poor substitute for glycosylation unless detergent was added to the microsomes. In contrast, glycosylation of tripeptide acceptors was not stimulated by detergent. Both of these findings suggest that the tripeptides are freely permeable to the microsomal membrane and support the earlier conclusion that glycosylation of proteins occurs at the luminal face of the microsomes. .