scholarly journals Synthesis of divinyl protochlorophyllide. Enzymological properties of the Mg-protoporphyrin IX monomethyl ester oxidative cyclase system

1991 ◽  
Vol 276 (3) ◽  
pp. 691-697 ◽  
Author(s):  
C J Walker ◽  
P A Castelfranco ◽  
B J Whyte
Keyword(s):  
Metal Ion ◽  
Osmotic Shock ◽  
Protoporphyrin Ix ◽  
Protein S ◽  
Cyclase Activity ◽  
Ph Optimum ◽  
Pellet Fraction ◽  
Octyl Glucoside ◽  
Blue Sepharose ◽  
Monomethyl Ester

The resolution and reconstitution of the Mg-protoporphyrin IX monomethyl ester oxidative cyclase system into a supernatant and a pellet fraction was accomplished by a procedure involving salt treatment followed by osmotic shock. Recombination of pellet and supernatant fractions was required for cyclase activity. This restoration effect could be demonstrated using either Mg-protoporphyrin IX or Mg-protoporphyrin IX monomethyl ester as the cyclase substrate in the presence or absence of S-adenosylmethionine. Pretreatment of the pellet fraction with either 8-hydroxyquinoline or desferal mesylate inhibited cyclase activity, indicating that there is a heavy-metal-ion requirement in this fraction. The cyclase supernatant protein(s) was not internalized by Sephadex G-50 and did not bind to Blue Sepharose, suggesting that it has a molecular mass of over 30 kDa and that it does not bind the cofactor NADPH. The cyclase supernatant protein did bind to MgProtoMe2-bound Sepharose and could be eluted by raising the pH to 9.7 in the presence of 4 mM-n-octyl glucoside. The pH optimum of the cyclase was 9.0. About a 40-fold purification of the cyclase supernatant protein was achieved by a combination of (NH4)2SO4 fractionation and phenyl-Sepharose chromatography.

Characterization of an octopamine-sensitive adenylate cyclase from insect brain (Mamestra configurata Wlk.)5

1979 ◽  
Vol 57 (3) ◽  
pp. 226-232 ◽  
Author(s):  
Robert P. Bodnaryk
Keyword(s):  
Enzyme Activity ◽  
Adenylate Cyclase ◽  
Metal Ion ◽  
Cyclase Activity ◽  
Mammalian Brain ◽  
Insect Brain ◽  
Ph Optimum ◽  
Mamestra Configurata ◽  
Specificity Effect

An adenylate cyclase present in the brain of the moth Mamestra configurata Wlk. that is stimulated selectively by low (micromolar) concentrations of octopamine has been characterized with respect to several properties. The optimum pH, optimum ATP:Mg2+ ratio, the concentration of ATP required for half-maximal and maximal reaction velocity, metal ion specificity, effect of NaF, and effects of GTP and 5′-guanylylimidodiphosphate were in general similar to those of catecholamine-sensitive adenylate cyclases from various regions of mammalian brain. However, ethylene glycol bis-(β-aminoethyl ether)-N,N-tetraacetic acid (EGTA), a calcium chelator, stimulated both basal and octopamine-sensitive enzyme activity in the insect brain, whereas in mammalian brain EGTA is usually observed to inhibit basal activity but not catecholamine-stimulated activity.Adenylate cyclase activity of the 47 000 g particulate fraction of the insect brain was almost undetectable in the absence of added GTP. Addition of saturating concentrations (100 μM) of GTP to the particles restored about 30% of the basal and octopamine-sensitive enzyme activity present in the homogenate. Addition of 100 000 g supernatant to the particles doubled both basal and octopamine-sensitive enzyme activity in the presence of saturating concentrations of GTP, indicating that in addition to GTP, a cytosolic factor(s) is necessary for enhanced adenylate cyclase activity.

Semi-purification procedures of prions from a prion-infected brain using sucrose has no influence on the nonenzymatic glycation of the disease-associated prion isoform

2016 ◽  
Vol 397 (2) ◽  
pp. 125-133 ◽  
Author(s):  
Yeong-Gon Choi ◽  
Jae-Il Kim ◽  
Eun-Kyoung Choi ◽  
Richard I. Carp ◽  
Yong-Sun Kim
Keyword(s):  
Colloidal Silica ◽  
Protein S ◽  
Core Region ◽  
Advanced Glycation ◽  
Nonenzymatic Glycation ◽  
Pellet Fraction ◽  
Sucrose Cushion ◽  
Advanced Glycation End Product ◽  
Modified Polymer

Abstract Previous studies have shown that the Nε-carboxymethyl group is linked to not only one or more N-terminal Lys residues but also to one or more Lys residues of the protease-resistant core region of the pathogenic prion isoform (PrPSc) in prion-infected brains. Using an anti-advanced glycation end product (AGE) antibody, we detected nonenzymatically glycated PrPSc (AGE-PrPSc) in prion-infected brains following concentration by a series of ultracentrifugation steps with a sucrose cushion. In the present study, the levels of in vitro nonenzymatic glycation of PrPSc using sucrose were investigated to determine whether sucrose cushion can artificially and nonenzymatically induce in vitro glycation during ultracentrifugation. The first insoluble pellet fraction following the first ultracentrifugation (PU1st) collected from 263K scrapie-infected brains was incubated with sucrose, glucose or colloidal silica coated with polyvinylpyrrolidone (percoll). None of the compounds in vitro resulted in AGE-PrPSc. Nonetheless, glucose and percoll produced AGEs in vitro from other proteins within PU1st of the infected brains. This reaction could lead to the AGE-modified polymer(s) of nonenzymatic glycation-prone protein(s). This study showed that PrPSc is not nonenzymatically glycated in vitro with sucrose, glucose or percoll and that AGE-modified PrPSc can be isolated and enriched from prion-infected brains.

Mutation in Mg-Protoporphyrin IX Monomethyl Ester Cyclase Causes Yellow and Spotted Leaf Phenotype in Rice

2019 ◽  
Vol 37 (4) ◽  
pp. 253-264 ◽  
Author(s):  
Chun Li ◽  
Furong Ma ◽  
Renjun Jiao ◽  
Congping Chen ◽  
Qian Wang ◽  
...  
Keyword(s):  
Protoporphyrin Ix ◽  
Leaf Phenotype ◽  
Monomethyl Ester

HIGH AFFINITY CALCIUM BINDING TO DOMAINES OF PROTEIN C THAT ARE HOMOLOGUS TO THE EPIDERMAL GROWTH FACTOR

1987 ◽  
Author(s):  
A KÖhlin ◽  
J Stenflo
Keyword(s):  
Calcium Ions ◽  
Calcium Ion ◽  
Calcium Binding ◽  
Plasma Proteins ◽  
Metal Ion ◽  
Protein C ◽  
Protein S ◽  
Protein Z ◽  
High Affinity ◽  
Epidermal Growth

In addition to γ-carboxyglutamic acid (Gla)-dependent calcium binding all of the vitamin K-dependent plasma proteins, except prothrombin, have one or two high affinity calcium binding sites that do not require the Gla residues. A common denominator among these proteins (factors IX, X, protein C, protein Z and protein S) is that they have domaines that are homologus to the epidermal growth factor (EGF) precursor. In factors VII,IX,X, protein C and in protein Z the aminoterminal of two EGF homology regions contain one residue of β-hydroxyaspartic acid (Hya) whereas in protein S the aminoterminal EGF homology region contains Hya and the three following contain one β-hydroxyasparagine residue each.In an attempt to elucidate the role of the EGF homology regions in the Gla independent calcium binding we have isolated a tryptic fragment (residue 44-138) from the light chain of human protein C. The fragment was isolated using a monoclonal antibody that recognizes a calcium ion stabilized epitope that is expressed both in intact protein C and in protein C lacking the Gla domaine.The antibody bound the isolated EGF homology region in the presence of calcium ions but not in EDTA containing buffer. A calcium ion titration showed half maximal binding at approximately 200 μM Ca2+. The metal ion induced conformational change in the isolated fragment was also studied with affinity purified rabbit antibodies against Gla domainless protein C. Antibodies that bound in the presence of calcium ions and that could be eluted with EDTA recognized the metal ion induced conformational change in the isolated EGF homology domain. Our results suggest that one or both of the EGF homology regions are involved in the Gla-independent high affinity calcium binding in the vitamin K-dependent plasma proteins.

scholarly journals The Ycf54 protein is part of the membrane component of Mg-protoporphyrin IX monomethyl ester cyclase from barley (Hordeum vulgareL.)

FEBS Journal ◽  
2014 ◽  
Vol 281 (10) ◽  
pp. 2377-2386 ◽  
Author(s):  
David Bollivar ◽  
Ilka Braumann ◽  
Kasper Berendt ◽  
Simon P. Gough ◽  
Mats Hansson
Keyword(s):  
Protoporphyrin Ix ◽  
Membrane Component ◽  
Monomethyl Ester

scholarly journals Phosphomonoesterase hydrolysis of polyphosphoinositides in rat kidney: Properties and subcellular localization of the enzyme system

1975 ◽  
Vol 150 (3) ◽  
pp. 537-551 ◽  
Author(s):  
P H Cooper ◽  
J N Hawthorne
Keyword(s):  
Phosphatase Activity ◽  
Metal Ion ◽  
Rat Kidney ◽  
Gradient Centrifugation ◽  
Sodium Deoxycholate ◽  
Subcellular Fractionation ◽  
Kidney Cortex ◽  
Ph Optimum ◽  
Triton X ◽  
Hydrolysis Of

Tthe properties of diphosphoinositide and triphosphoinositide phosphatases from rat kidney homogenate were studied in an assay system in which non-specific phosphatase activity was eliminated. The enzymes were not completely metal-ion dependent and were activated by Mg2+. The detergent sodium deoxycholate, Triton X-100 and Cutscum inhibited the reaction; cetyltrimethylammonium bromide only activated when added with the subtrates and in the presence Mg2+. Both enzymes had a pH optimum of 7.5. Ca2+ and Li+ both activated triphosphoinositide phosphatase, but Ca2+ inhibited and L+ had little effect on diphosphoinositide phosphatase. Cyclic AMP had no effect on either enzyme. The enzymes were three times more active in kidney cortex than in the medulla. On subcellular fractionation of kidney-cortex homogenates by differential and density-gradient centrifugation, the distribution of the enzymes resembled that of thiamin pyrophosphatase (assayed in the absence of ATP), suggesting localization in the Golgi complex. However, the distribution differed from that of the liver Golgimarker galactosyltransferase. Activities of both diphosphoinositide and triphosphoinositide phosphatases and thiamin pyrophosphatase were low in purified brush-border fragments. Further experiments indicate that at least part of the phosphatase activity is soluble.

scholarly journals Catecholamine-sensitive adenylate cyclase of caudate nucleus and cerebral cortex. Effects of guanine nucleotides

1977 ◽  
Vol 164 (1) ◽  
pp. 67-74 ◽  
Author(s):  
P V Sulakhe ◽  
N L Leung ◽  
A T Arbus ◽  
S J Sulakhe ◽  
S H Jan ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Cerebral Cortex ◽  
Adenylate Cyclase ◽  
Caudate Nucleus ◽  
Protein S ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Biphasic Effect ◽  
Site Binding ◽  
Stimulation Of

1. GTP and GMP-P(NH)P (guanyl-5'-yl imidodiphosphate) were observed to increase the stimulation of neural adenylate cyclase by dopamine (3,4-dihydroxyphenethylamine) and noradrenaline. 2. GMP-P(NH)P had a biphasic effect on the enzyme activity. 3. Preincubation of membranes with GMP-P(NH)P activated the enzyme by a process dependent on time and temperature. Catecholamines increased the speed and the extent of this activation. 4. Membrane fractions contained high- and low-affinity sites for GMP-P(NH)P binding: this binding was due to protein(s) of the membrane preparations. 5. Low-affinity-site binding of GMP-P(NH)P appeared to be related to the stimulatory effect on the adenylate cyclase activity.

Amino Acid Residues His183 and Glu264 inBacillus subtilisFerrochelatase Direct and Facilitate the Insertion of Metal Ion into Protoporphyrin IX†,‡

Biochemistry ◽  
2007 ◽  
Vol 46 (1) ◽  
pp. 87-94 ◽  
Author(s):  
Mattias D. Hansson ◽  
Tobias Karlberg ◽  
Muhammad Arys Rahardja ◽  
Salam Al-Karadaghi ◽  
Mats Hansson
Keyword(s):  
Amino Acid ◽  
Metal Ion ◽  
Protoporphyrin Ix ◽  
Amino Acid Residues
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