Modulation of the Peptide Backbone Conformation by the Selenoxo Photoswitch
摘要:
Photocontrol of the backbone conformation is a useful step forward in regulating the bioactivities of peptides and proteins by means of external signals. In the present work, the selenium analogue of a peptide bond was introduced into tetrapeptides to obtain surprisingly stable selenoxo peptides. Selenoxo peptide bonds allow for a marked increase of cis content in the photostationary state of peptide chains when irradiated with UV light near 290 nm. Slow thermal re-equilibration with rate constants between 9.9 x 10(-4) and 1.3 x 10(-5) s(-1) shows that the transient nonequilibrium conformations exist long enough to monitor the isomer specificity of biochemical reactions.
A compound of Formula (I) wherein R is a biomolecular residue, or derivative thereof, of a C-terminal amide biomolecule which is activated by the action of PAM; and X is O or CH2 or a salt, or prodrug thereof.
Two sides to a nitrogen: The cis to trans isomerization of selenoxo peptides in alkaline conditions is rationalized in terms of rapid nitrogeninversion of the tautomeric selenoimidate anion [C(Se−)N] (see scheme), which increases the isomerization rate by about 30‐fold as compared to the rotational pathway of the [CSeNH] form. The current work identifies the imino tautomer of a selenoxo peptide
Immobilized fluorogenic substrates for enzymes; and processes for their
申请人:The Research Foundation of the State University of New York
公开号:US04897444A1
公开(公告)日:1990-01-30
An immobilized fluorogenic substrate useful in processes for identifying and quantifying, intra- and extra-cellularly, and mammalian body fluids, as well as animal cell abstracts is disclosed. The immobilized fluorogenic substrate has the structure R.sub.1 --NH--R.sub.4 --R.sub.2 --R.sub.3 wherein R.sub.1 represents an enzyme-specific oligopeptide; R.sub.2 represents a spacer group which is methylenecarbonyloxy, a methylenecarboxamido, or a methylanesulfonamido group attached to a polymethylene chain which itself has a functional group suitable for coupling with a polymer; R.sub.3 represents a biologically inert polymer; and R.sub.4 represents a fluorogenic moiety.
Inhibition of Peptidylglycine α-Amidating Monooxygenase by Exploitation of Factors Affecting the Stability and Ease of Formation of Glycyl Radicals
作者:Brendon J. W. Barratt、Christopher J. Easton、David J. Henry、Iris H. W. Li、Leo Radom、Jamie S. Simpson
DOI:10.1021/ja046204n
日期:2004.10.1
Peptidylglycine alpha-amidating monooxygenase catalyzes the biosynthesis of peptide hormones through radical cleavage of the C-terminal glycine residues of the corresponding prohormones. We have correlated ab initio calculations of radical stabilization energies and studies of freeradical brominations with the extent of catalysis displayed by peptidylglycine alpha-amidating monooxygenase, to identify
肽基甘氨酸 α-酰胺化单加氧酶通过自由基切割相应激素原的 C 端甘氨酸残基来催化肽激素的生物合成。我们将自由基稳定能的从头计算和自由基溴化的研究与肽基甘氨酸 α-酰胺化单加氧酶显示的催化程度相关联,以确定酶抑制剂的类别。特别是我们发现,在密切相关的系统中,用甘氨酸取代乙醇酸使计算的自由基稳定能降低了 34.7 kJ mol(-1),在四氯化碳中回流时用 N-溴代琥珀酰亚胺的溴化速率降低了一个因子至少 2000,并停止单加氧酶的催化作用,同时保持与酶的结合。