geoscience.net logo
+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

Probing substrate backbone function in prolyl oligopeptidase catalysis: Large positional effects of peptide bond monothioxylation


, : Probing substrate backbone function in prolyl oligopeptidase catalysis: Large positional effects of peptide bond monothioxylation. European Journal of Biochemistry 245(2): 381-385

Site-specific effects on the catalytic activity of prolyl oligopeptidase from human placenta were studied using oligopeptide substrates in which a peptide bond has been replaced by a thioxo peptide bond. Two series of tetrapeptide-4-nitroanilides, Ala-Gly-Pro-Phe-NH-Np and Ala-Ala-Pro-Phe-NH-Np, along with all possible monothioxylated derivatives, were synthesised and k-cat and K-m values were determined for proteolytic cleavage at the Pro-Phe bond. Regardless of either Gly or Ala in the P-2 subsite, tetrapeptides were rendered uncleavable by thioxylation at the Pro-Phe linkage. As a result, Ala-Xaa-Pro-psi(CS-NH)-Phe-NH-Np (Xaa = Gly or Ala) displayed competitive inhibition with K-i-values of 12 JIM and 44 mu-M, respectively. Furthermore, in controlling proteolytic susceptibility of the substrates, cooperation of the P-3-P-2 thioxylation site and the side chain at the P-2 subsite was obtained. Thioxylation at this position enhanced k-cat/K-m fivefold in the Gly series, but led to a 1.7-fold decrease in the Ala series of substrates. With respect to the Xaa-Pro peptide bond, all of the substrates underwent cis/trans isomerisation, thus presenting two stable conformers to the protease. However, the magnitudes of the isomerisation constants suggested that neither isomerisation rates nor cis/trans equilibria can explain the effect of thioxylation on the steady-state constants of proteolysis.

US$19.90

PMID: 9151967

DOI: 10.1111/j.1432-1033.1997.00381.x


Other references

Chan-Chien, C.; Lee, C.H.; Chen, P.C.; Lin, D.Y.; Wu, C.S.; Liaw, Y.F., 1981: Peritoneoscopic guided aspiration cytology in the diagnosis of liver malignancy. Taiwan Yi Xue Hui Za Zhi. Journal of the Formosan Medical Association 80(7): 718-723

Valodzin U.H.; Kartel M.A.; Lisowskaya Z.I., 1972: Criteria of radioactivity of plants. Vyestsi Akademii Navuk BSSR Syeryya Biyalahichnykh Navuk (1): 65-68

Haddad, B.; Uzan, M.; Tchobroutsky, C.; Uzan, S.; Papiernik-Berkhauer, E., 1993: Predictive value of uterine Doppler waveform during pregnancies complicated by diabetes. Diabetes, whether or not it is insulin deficient, is frequently associated with vascular complications during pregnancies. It is accepted nowadays that the uterine artery velocity waveform is predictive concerning pregnancy-induced hypertension (P...

Weber, B.L.; Nathanson, K.L., 2000: Low penetrance genes associated with increased risk for breast cancer. Much effort in recent years has been focused on understanding the factors that contribute to breast cancer risk. Two major susceptibility alleles, BRCA1 and BRCA2, have been identified, and the prevalence and penetrance of mutations in these genes...

Janisch, R., 1964: Sub-Microscopic Structure Of Injured Surface Of Paramecium Caudatum. Nature 204: 200-201

Chamiso, B., 1995: Rupture of pregnant uterus in Shashemene General Hospital, south Shoa, Ethiopia (a three year study of 57 cases). During September 1989 to August 1992, in South Shoa, Ethiopia, 57 cases of uterine rupture were admitted to Shashemene General Hospital. During the same time period, there were 2185 deliveries, for a uterine rupture incidence rate of 2.6%. 89.4% o...

Dybing, E.; Saxholm, H.J.; Aune, T.; Wirth, P.J.; Thorgeirsson, S.S., 1981: Studies on mutagenic and carcinogenic N-substituted aryl compounds: cosmetics and drugs. We aimed our studies toward gaining an understanding of some of the reactions and pathways involved in the metabolism and activation of the aromatic diamines used in hair dyes and of phenacetin used in analgesic mixtures. Comparison of the data ob...

Shorr, A.S., 1987: The physician/hospital joint venture. Developing a win/win strategy for success. Part II: Joint venture strategies and considerations. This four part series, "The Physician/Hospital Joint Venture: Developing a Win/Win Strategy," examines the philosophical basis of marketing to physicians, the options for the organization in formulating a strategy for joint venture devel...

Germain E., 1970: Analytical experiment of the mode of action of vigorous grafting stocks increasing the development of the grafted tree. Proceedings Of The International Horticultural Congress: 172

Mark Greener, 2011: Prions, Parkinsons disease and the search for a new generation of treatments. Recent research suggests that aggregates of cytosolic proteins such as ?-synuclein may spread in a manner similar to prions in certain neurodegenerative diseases. Mark Greener explains how drugs that can reduce formation or increase clearance of t...