Biochemical characteristics of a nitroreductase with diverse substrate specificity fromStreptomyces mirabilisDUT001

2018 ◽  
Vol 66 (1) ◽  
pp. 33-42 ◽  
Author(s):  
Jun Yang ◽  
Jing Bai ◽  
Mingbo Qu ◽  
Bo Xie ◽  
Qing Yang
Keyword(s):  
Substrate Specificity ◽  
Biochemical Characteristics

scholarly journals Catalytic residues, substrate specificity, and role in carbon starvation of the 2-hydroxy FA dioxygenase Mpo1 in yeast

2020 ◽  
Vol 61 (7) ◽  
pp. 1104-1114
Author(s):  
Keisuke Mori ◽  
Takashi Obara ◽  
Naoya Seki ◽  
Masatoshi Miyamoto ◽  
Tatsuro Naganuma ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Oxidation Reaction ◽  
Degradation Pathway ◽  
Carbon Starvation ◽  
Membrane Topology ◽  
Yeast Protein ◽  
Biochemical Characteristics ◽  
Catalytic Residues ◽  
Long Chain Base ◽  
Long Chain

The yeast protein Mpo1 belongs to a protein family that is widely conserved in bacteria, fungi, protozoa, and plants, and is the only protein of this family whose function has so far been elucidated. Mpo1 is an Fe2+-dependent dioxygenase that catalyzes the α-oxidation reaction of 2-hydroxy (2-OH) long-chain FAs (LCFAs) produced in the degradation pathway of the long-chain base phytosphingosine. However, several biochemical characteristics of Mpo1, such as its catalytic residues, membrane topology, and substrate specificity, remain unclear. Here, we report that yeast Mpo1 contains two transmembrane domains and that both its N- and C-terminal regions are exposed to the cytosol. Mutational analyses revealed that three histidine residues conserved in the Mpo1 family are especially important for Mpo1 activity, suggesting that they may be responsible for the formation of coordinate bonds with Fe2+. We found that, in addition to activity toward 2-OH LCFAs, Mpo1 also exhibits activity toward 2-OH very-long-chain FAs derived from the FA moiety of sphingolipids. These results indicate that Mpo1 is involved in the metabolism of long-chain to very-long-chain 2-OH FAs produced in different pathways. We noted that the growth of mpo1Δ cells is delayed upon carbon deprivation, suggesting that the Mpo1-mediated conversion of 2-OH FAs to nonhydroxy FAs is important for utilizing 2-OH FAs as a carbon source under carbon starvation. Our findings help to elucidate the as yet unknown functions and activities of other Mpo1 family members.

scholarly journals N-acetylation of drugs. Observations on the properties of partially purified N-acetyltransferase from peripheral blood of rabbit

1980 ◽  
Vol 187 (1) ◽  
pp. 157-162 ◽  
Author(s):  
G S Drummond ◽  
H C Kelker ◽  
W W Weber
Keyword(s):  
Substrate Specificity ◽  
Peripheral Blood ◽  
Acetylator Phenotype ◽  
Evolutionary Origin ◽  
Partial Purification ◽  
Ph Optimum ◽  
Biochemical Characteristics ◽  
Effect Rate ◽  
Rabbit Blood ◽  
Cation Effect

A method is described for the partial purification of N-acetyltransferase (EC 2.3.1.5) from peripheral blood of rabbit. This enzyme purified from both rapid- and slow-ioniazid-acetylator phenotype rabbits was examined with regard to stability, substrate specificity, cation effect, rate of inactivation, temperature and pH optimum. Data show that in the biochemical characteristics examined the enzyme is independent of acetylator phenotype. The possible significance of these findings to the evolutionary origin of drug-acetylating enzymes in rabbit blood and liver is discussed.

Microtubule Dynamics and Organelle Transport in Reticulomyxa

1990 ◽  
Vol 48 (3) ◽  
pp. 194-195
Author(s):  
Yih-Tai Chen ◽  
Ursula Euteneuer ◽  
Ken B. Johnson ◽  
Michael P. Koonce ◽  
Manfred Schliwa
Keyword(s):  
Plasma Membrane ◽  
Light Microscopy ◽  
Cytoplasmic Dynein ◽  
Living Cells ◽  
Microtubule Dynamics ◽  
Model Systems ◽  
Organelle Transport ◽  
Biochemical Characteristics ◽  
Dependent Transport

The application of video techniques to light microscopy and the development of motility assays in reactivated or reconstituted model systems rapidly advanced our understanding of the mechanism of organelle transport and microtubule dynamics in living cells. Two microtubule-based motors have been identified that are good candidates for motors that drive organelle transport: kinesin, a plus end-directed motor, and cytoplasmic dynein, which is minus end-directed. However, the evidence that they do in fact function as organelle motors is still indirect.We are studying microtubule-dependent transport and dynamics in the giant amoeba, Reticulomyxa. This cell extends filamentous strands backed by an extensive array of microtubules along which organelles move bidirectionally at up to 20 μm/sec (Fig. 1). Following removal of the plasma membrane with a mild detergent, organelle transport can be reactivated by the addition of ATP (1). The physiological, pharmacological and biochemical characteristics show the motor to be a cytoplasmic form of dynein (2).

Substrate specificity and inducibility of TACE (tumour necrosis factor α-converting enzyme) revisited: the Ala-Val preference, and induced intrinsic activity

2003 ◽  
Vol 70 ◽  
pp. 39-52 ◽  
Author(s):  
Roy A. Black ◽  
John R. Doedens ◽  
Rajeev Mahimkar ◽  
Richard Johnson ◽  
Lin Guo ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Recent Work ◽  
Tumour Necrosis Factor ◽  
Tumour Necrosis ◽  
Transforming Growth Factor ◽  
Intrinsic Activity ◽  
Converting Enzyme ◽  
Tumour Necrosis Factor Α ◽  
Factor Α ◽  
Necrosis Factor

Tumour necrosis factor α (TNFα)-converting enzyme (TACE/ADAM-17, where ADAM stands for a disintegrin and metalloproteinase) releases from the cell surface the extracellular domains of TNF and several other proteins. Previous studies have found that, while purified TACE preferentially cleaves peptides representing the processing sites in TNF and transforming growth factor α, the cellular enzyme nonetheless also sheds proteins with divergent cleavage sites very efficiently. More recent work, identifying the cleavage site in the p75 TNF receptor, quantifying the susceptibility of additional peptides to cleavage by TACE and identifying additional protein substrates, underlines the complexity of TACE-substrate interactions. In addition to substrate specificity, the mechanism underlying the increased rate of shedding caused by agents that activate cells remains poorly understood. Recent work in this area, utilizing a peptide substrate as a probe for cellular TACE activity, indicates that the intrinsic activity of the enzyme is somehow increased.

Abstract #803: Cushing Disease Due to Pituitary Macroadenoma: Biochemical Characteristics in a Pediatric Cohort

2015 ◽  
Vol 21 ◽  
pp. 148-149
Author(s):  
Ricardo Correa ◽  
Maria Batsis ◽  
Prashant Chittiboina ◽  
Pooja Raghavan ◽  
Elena Belyavskaya ◽  
...  
Keyword(s):  
Pituitary Macroadenoma ◽  
Cushing Disease ◽  
Biochemical Characteristics

Abstract #856 A Case Series Review of Clinical and Biochemical Characteristics of Pituitary Abcess in Mexican Patients

2018 ◽  
Vol 24 ◽  
pp. 202-203
Author(s):  
Mireya Perez-Guzman ◽  
Alfredo Nava de la Vega ◽  
Arturo Pena Velarde ◽  
Tania Raisha Torres Victoria ◽  
Froylan Martinez-Sanchez ◽  
...  
Keyword(s):  
Case Series ◽  
Biochemical Characteristics ◽  
Mexican Patients

The tonoplast H+pyrophosphatase of radish seedlings: biochemical characteristics

1991 ◽  
Vol 83 (3) ◽  
pp. 339-345 ◽  
Author(s):  
Maria Chiara Pugliarello ◽  
Franca Rasi-Caldogno ◽  
Maria Ida De Michelis ◽  
Claudio Olivari
Keyword(s):  
Biochemical Characteristics ◽  
Radish Seedlings
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