Two sulfhydryl groups near the active site of thiolase I from porcine heart: modification of thiolase with the fluorescent thiol reagent S-mercurio-N-dansyl-L-cysteine

Biochemistry ◽  
1982 ◽  
Vol 21 (24) ◽  
pp. 6112-6118 ◽  
Author(s):  
Elzbieta Izbicka-Dimitrijevic ◽  
Hiram F. Gilbert
Keyword(s):  
Active Site ◽  
Sulfhydryl Groups ◽  
Porcine Heart ◽  
Thiol Reagent

Multiple oxidation products of sulfhydryl groups near the active site of thiolase I from porcine heart

Biochemistry ◽  
1984 ◽  
Vol 23 (19) ◽  
pp. 4318-4324 ◽  
Author(s):  
Elzbieta Izbicka-Dimitrijevic ◽  
Hiram F. Gilbert
Keyword(s):  
Active Site ◽  
Sulfhydryl Groups ◽  
Oxidation Products ◽  
Porcine Heart

scholarly journals Formation of N-hydroxy-N-arylacetamides from nitroso aromatic compounds by the mammalian pyruvate dehydrogenase complex

1993 ◽  
Vol 290 (3) ◽  
pp. 783-790 ◽  
Author(s):  
T Yoshioka ◽  
T Uematsu
Keyword(s):  
Pyruvate Dehydrogenase ◽  
Active Site ◽  
Aromatic Compounds ◽  
Pyruvate Dehydrogenase Complex ◽  
Catalytic Efficiency ◽  
Nitroso Compounds ◽  
Factors Affecting ◽  
Porcine Heart ◽  
Alkyl Groups ◽  
Dehydrogenase Complex

Bovine, human and porcine heart mitochondria and isolated porcine heart pyruvate dehydrogenase complex (PDHC) pyruvate-dependently form N-hydroxy-N-arylacetamides from nitroso aromatic compounds, including carcinogenic 4-biphenyl and 2-fluorenyl derivatives. The PDHC-catalysed formation of N-hydroxyacetanilide (N-OH-AA) from nitrosobenzene (NOB), through a Ping Pong mechanism, is optimum at pH 6.8 and is accelerated by thiamin pyrophosphate, but is inhibited by thiamin thiazolone pyrophosphate and ATP. Km pyruvate in the reaction is independent of pH over the range tested, whereas KmNOB increases at lower pH, owing to ionization of an active-site functional group of pKa 6.3. The enzymic ionization decreases log (Vmax/KmNOB). Isolated pyruvate dehydrogenase (E1), a constitutive enzyme of PDHC, forms N-OH-AA by itself and has comparable kinetic parameters to those of the PDHC-catalysed N-OH-AA formation. The catalytic efficiency of PDHC in the formation of N-hydroxy-N-arylacylamides, due to the steric limitation of the active site of E1, is lowered both by bulky alkyl groups of alpha-oxo acids and by p-substituents (but not an o-substituent) on nitrosobenzenes. These nitroso compounds serve as electrophiles in the reaction in which the reductive acetylation step is rate-limiting. The reaction mechanism and other factors affecting N-hydroxy-N-arylacylamide formation are discussed.

The Sulfhydryl Groups Involved in the Active Site of Myosin B Adenosinetriphosphatase

1977 ◽  
Vol 82 (4) ◽  
pp. 1085-1092 ◽  
Author(s):  
Tsuneyoshi HORIGOME ◽  
Tatsuhisa YAMASHITA
Keyword(s):  
Active Site ◽  
Sulfhydryl Groups ◽  
Myosin B

Design and Characterization of a Labeling Reagent for Covalent Immobilization of Glutathione-S-Transferase

2019 ◽  
Vol 11 (11) ◽  
pp. 1547-1560
Author(s):  
Chao Xia ◽  
Jinpeng Lu ◽  
Bangtian Xu ◽  
Xiaolei Hu ◽  
Yixian Jing ◽  
...  
Keyword(s):  
Active Site ◽  
Covalent Immobilization ◽  
Sulfhydryl Groups ◽  
Submicron Particles ◽  
Primary Amines ◽  
Glutathione S Transferase ◽  
Irreversible Inhibitor ◽  
Hydrophobic Compounds ◽  
Hydrophobic Moiety

A labeling reagent against S. japonicum glutathione-S-transferase (sjGST), denoted as Br-I, was designed, prepared and characterized for covalent immobilization of sjGST on magnetic submicron particles (MSP). Br-I had a large hydrophobic moiety for binding to one active site of sjGST, an extended flexible bromoacetylamide moiety for covalent linkage to any of the accessible amino/sulfhydryl groups through nucleophilic substitution. In addition, Br-I had an extended carboxyl group for conjugation with aliphatic primary amines on the MSP, besides a flexible sketch to link those moieties together. Free Br-I was both a substrate/pro-inhibitor and a monovalent irreversible inhibitor of sjGST. There was >75% inactivation of sjGST after half an hour with free Br-I in excess to the sjGST active site, but only sulfhydryl groups far away from the active site were modified when their quantities were comparable. After conjugation to the MSP, Br-I selectively immobilized sjGST in the presence of alkaline phosphatase as a competitor. The treatment of immobilized sjGST with the mixture of free Br-I and GSH reduced unfavorable adsorption of small hydrophobic compounds. Therefore, after conjugation to biomaterials, Br-I showed promise for covalent site-specific immobilization of sjGST-fused targeted proteins.

scholarly journals The histochemical distribution of protein bound sulfhydryl groups in human epidermis by the new staining method.

1979 ◽  
Vol 27 (5) ◽  
pp. 942-946 ◽  
Author(s):  
H Ogawa ◽  
A Taneda ◽  
Y Kanaoka ◽  
T Sekine
Keyword(s):  
Cell Membrane ◽  
Stratum Corneum ◽  
Staining Method ◽  
Sulfhydryl Groups ◽  
The Other ◽  
Human Epidermis ◽  
Horny Layer ◽  
Intercellular Spaces ◽  
Sh Groups ◽  
Thiol Reagent

Recently, we synthesized a new fluorescent thiol reagent, N-(7-dimethylamino-4-methylcoumarinyl)-maleimide (DACM) which is nonfluorescent by itself but will react readily with -SH groups to form highly fluorescent addition products. By the use of this reagent, we studied the localization and concentration of -SH groups and S--S linkages in the human epidermis. The distribution of -SH groups in living layers was abundant in cytoplasm but not in nuclei. The fluorescence was concentrated on the cell membrane or intercellular spaces (MIC parts) and was increased at the spino-granular junction. In the horny layer, the fluorescence of the MIC parts appeared brilliantly in the lower layers and decreased gradually. On the other hand, the fluorescence of cytoplasm in keratinized cells in the stratum corneum was faint. The localization of S--S linkages was not a characteristic of the living layers, but appeared abruptly at the junction of living and horny layers. The fluorescence was localized to the MIC parts and disappeared gradually. The distribution of S--S linkages appeared to be very low in the cytoplasm of keratinized cells. No substantial fluorescence was localized on keratohyalin granules even after reduction.

Evidence for the proximity of two sulfhydryl groups at the active site of 6-phosphogluconate dehydrogenase

1978 ◽  
Vol 186 (2) ◽  
pp. 406-410 ◽  
Author(s):  
Mario Rippa ◽  
Marco Signorini ◽  
Alessandro Pernici ◽  
Franco Dallocchio
Keyword(s):  
Active Site ◽  
Sulfhydryl Groups ◽  
Phosphogluconate Dehydrogenase
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