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991.
992.
William U. Primrose Neil E. Mackenzie J. Paul G. Malthouse A. Ian Scott 《Bioorganic chemistry》1985,13(4)
The formation of an enzyme-inhibitor adduct between bovine trypsin and [2-13C]p-amidinophenylpyruvic acid has been investigated by 13C NMR spectroscopy. The observation of a resonance at 100.8 ppm demonstrates that the hemiketal formed between the hydroxyl of serine-195 and the 2-13C carbon of p-amidinophenylpyruvic acid is sp3 hybridized with no significant deviation from tetrahedral geometry. It is shown that stabilization of the hemiketal oxyanion if it occurs is less effective than in chloromethylketone inhibitor complexes. The tetrahedral adduct is stable from pH 3 to 8. The mechanisms of breakdown of the tetrahedral adduct at pH extremes are discussed. 相似文献
993.
Cyclic GMP-dependent protein kinase from bovine lung and cyclic AMP-dependent protein kinase from bovine heart are inactivated by Nα-tosyl-L-lysine chloromethylketone (TLCK) in the presence of cyclic GMP and cyclic AMP, respectively. The inactivation of both protein kinases is pseudo-first order, suggesting the rate limiting step is beyond the binding of TLCK. Cyclic GMP-dependent protein kinase is inactivated less than as rapidly as cyclic AMP-dependent protein kinase, although it shows a higher apparent affinity for TLCK. Cyclic AMP stimulated the rate of inactivation of cyclic AMP-dependent protein kinase 10-fold but cyclic GMP stimulated the rate of inactivation of cyclic GMP-dependent protein kinase only 1.5-fold. The rate of inactivation of cyclic GMP-dependent protein kinase by TLCK is sufficiently rapid (half-time of about 30 min at 37°C with 2 mM TLCK) to account for the effects of TLCK on cell growth observed by others. 相似文献
994.
995.
996.
S. A. Chapman R. E. Bonshek R. W. Stoddart C. J. P. Jones K. R. Mackenzie E. ODonoghue D. McLeod 《The Histochemical journal》1995,27(11):869-881
Summary Twelve specimens of resin-embedded human trabecular meshwork were probed with a panel of 21 biotinylated lectins, using an
avidin-biotin peroxidase revealing system, in order to determine the normal pattern of saccharide expression in this tissue.
High-mannose, intermediate and hybrid N-linked glycans, and complex N-linked bisected and non-bisected bi/tri-antennate glycans,
as shown by the binding ofCanavalia ensiformis (ConA),Pisum sativum (PSA),Lens culinaris (LCA) agglutinins andPhaseolus vulgaris erythroagglutinin (ePHA), were strongly expressed by the canal of Schlemm endothelium and juxtacanalicular tissue, but less
so by the corneoscleral meshwork. Highly branched complex glycans were not found, as there was no binding byPhaseolus vulgaris leukoagglutinin (1PHA). Sialyl residues, especially thoseα2,6-linked as demonstrated by strongSambucus nigra (SNA) lectin staining, were also abundant in this area.N-acetyllactosamine sequences and some O-linked glycans were present in the trabecular meshwork, as shown bySolanum tuberosum (STA),Datura stramonium (DSA), andJacalin (Jac) lectin binding, while fucose residues were not detected byTetragonolobus purpureas (LTA) orUlex europaeus-1 (UEA-1) agglutinins. These results indicate similarities with renal glomerular and vascular endothelium, although the lack
of binding with UEA-1 agglutinin suggests differences which may relate to the specialized function of the trabecular meshwork.
This study provides a baseline for comparative analysis of the glycans of human trabecular meshwork in pathological conditions
such as primary open-angle glaucoma. 相似文献
997.
998.
999.
Ida S. Owens Peter I. Mackenzie 《Biochemical and biophysical research communications》1982,109(4):1075-1082
Solubilized mouse liver microsomes were subjected to chromatofocusing using a pH 9.5 to 6.0 gradient. UDP-glucuronosyltransferase activity was assayed using 12 benzo[a]pyrene phenols as substrates. The rank of microsomal activity for the phenols was as follows: 12 > 10 > 4 > 1 > 7 > 5 > 8 > 9 > 3 > 11 > 6 > 2. Fractions separated on chromatofocusing according to isoelectric point indicated that 3-, 10-, 11-, and 12-hydroxybenzo[a]pyrene were conjugated primarily by a high pI (~8.5) activity(s), 2-, 6-, 8-, and 9-hydroxybenzo[a]pyrene were conjugated primarily by a low pI (~6.7) activity(s), and 1-, 4-, 5-, and 7-hydroxybenzo[a]pyrene were conjugated equally well by high and low pI forms. 相似文献
1000.
Monique Simonoff Yvan Llabador Charles Hamon Arthur Mackenzie Peers Gabriel Nicolas Simonoff 《Biological trace element research》1984,6(5):431-439
Plasma chromium concentrations have been determined for 150 patients. These were subjected to coronary artery cineangiography and thereby divided into three groups: group CAD (those with coronary artery disease), group HD (those with heart disease, but no CAD) and group N (those with no CAD and no HD). Weighted, average chromium levels for these groups were 1.05, 1.72, and 8.51 ng/mL, respectively. The distributions of plasma chromium levels for the three groups suggest that an upper limit for plasma chromium may be established (6 ng/mL in this work) beyond which CAD may be considered to be extremely unlikely, thus eliminating the need for a certain number of cineangiographic examinations. 相似文献