Search results for " enzyme"

Parathyroid hormone-related peptide and 8701-BC breast cancer cell growth and invasion in vitro: evidence for growth-inhibiting and invasion-promotin…

1995

It has been previously reported that 8701-BC cells, derived from a primary carcinoma of the breast, constitutively express parathyroid hormone-related peptide (PTHrP) gene and that N-terminal PTHrP immunoreactivity can be found in cell medium. Here we have firstly measured immunoreactive PTHrP in 8701-BC cell medium using antibodies raised against midregion and C-terminal fragments, and also demonstrated the expression of PTH/PTHrP receptor by 8701-BC cells. Secondly, we have examined the role, if any, elicited by diverse PTHrP domains on 8701-BC cell proliferation, and invasive behaviour in vitro related to production of extracellular proteolytic enzymes. Our data show that PTHrP [1-34], a…

Variants of the

2019

The Gram-positive soil bacterium Bacillus subtilis relies on the glutamine synthetase and the glutamate synthase for glutamate biosynthesis from ammonium and 2-oxoglutarate. During growth with the carbon source glucose, the LysR-type transcriptional regulator GltC activates the expression of the gltAB glutamate synthase genes. With excess of intracellular glutamate, the gltAB genes are not transcribed because the glutamate-degrading glutamate dehydrogenases (GDHs) inhibit GltC. Previous in vitro studies revealed that 2-oxoglutarate and glutamate stimulate the activator and repressor function, respectively, of GltC. Here, we have isolated GltC variants with enhanced activator or repressor fu…

Substrate specificity screening of oat (Avena sativa) seeds aminopeptidase demonstrate unusually broad tolerance in S1 pocket.

2012

Aminopeptidases are proteolytic enzymes that remove one amino acid at a time from N-terminus of peptidic substrates. In plants, inhibitors of aminopeptidases can find potential applications in agriculture as herbicides. In this report we have used a library of fluorogenic derivatives of natural and unnatural amino acids for substrate specificity profiling of oat (Avena sativa) aminopeptidase. Interestingly, we have found that this enzyme recognizes effectively among the natural amino acids basic residues like Arg and Lys, hydrophobic Phe, Leu and Met, but also to some extent acidic residues Asp and Glu. In the case of unnatural amino acids hydrophobic residues (hPhe and hCha) and basic hArg…

Odorants' metabolism in Human: a critical role in odor perception revealed

2018

The NAOMI (Nasal Odorant Metabolites) consortium: an international, multidisciplinary consortium investigating how metabolites resulting from nasal e…

2021

International audience; A functional sense of smell is essential for evaluating and enjoying food, receiving information about conspecifics, and detecting threats via airborne chemical cues. Olfactory dysfunction has been associated with an impaired quality of life, reflected by a higher incidence of undesirable mental states such as depression and social insecurity. Addressing and overcoming related olfactory dysfunction issues require a detailed understanding of peripheral and central processes involved in olfaction. Consequently, there is a growing body of research unravelling molecular and cellular interactions that shape olfactory sensation. Recent studies have demonstrated that in the…

Degradation of an alkaloid pheromone from the pale-brown chafer, Phyllopertha diversa (Coleoptera: Scarabaeidae), by an insect olfactory cytochrome P…

1999

AbstractThe pale-brown chafer, Phyllopertha diversa, utilizes an unusual alkaloid, 1,3-dimethyl-2,4-(1H,3H)-quinazolinedione, as its sex pheromone. This compound is rapidly degraded in vitro by the antennal protein extracts from this scarab beetle. Demethylation at the N-1 position and hydroxylation of the aromatic ring have been identified as the major catabolic pathways. The enzyme responsible for the pheromone degradation is membrane-bound, requires NAD(P)H for activity and is sensitive to cytochrome P450 inhibitors, such as proadifen and metyrapone. The ability to metabolize this unusual pheromone was not detected in 12 species tested, indicating that the P450 system, specific to male P…

Plasma PAF-acetylhydrolase in patients with coronary artery disease: results of a cross-sectional analysis.

2003

Inflammation underlies both onset and perpetuation of atherosclerosis. Plasma lipoproteins transport the platelet-activating factor-acetylhydrolase (PAF-AH) with potentially anti-inflammatory activities. Our aim was to determine whether PAF-AH activity was associated with inflammatory markers and with coronary artery disease (CAD). PAF-AH activity and a panel of inflammatory mediators were measured in plasma of 496 patients with CAD and in 477 controls; 276 patients presented with stable angina pectoris and 220 with acute coronary syndrome (ACS). Individuals within the highest quartile of PAF-AH activity had an 1.8-fold increase in CAD risk [95% confidence interval (CI), 1.01 to 3.2; P = 0.…

Purification and partial characterization of aminopeptidase from barley (Hordeum vulgare L.) seeds.

2013

Aminopeptidases (EC 3.4.11) are proteolytic enzymes, which hydrolyze one amino acid from N-terminus of peptidic substrates. Inhibitors of plant aminopeptidases can find an application in agriculture as herbicides. Isolation and partial characterization of aminopeptidase from barley (Hordeum vulgare L.) seeds has been described. The enzyme was purified to molecular homogeneity using a six-step purification procedure (precipitation with (NH4)2SO4, followed by chromatography on Sephadex G-25, DEAE-Sepharose, Sephacryl HR 300, Macro-Prep Q and Phenyl-Sepharose HP columns). The enzyme was purified 365-fold with recovery above 18%. The molecular weight of the purified enzyme was determined by SDS…

Primer estudio experimental sobre los efectos de la digestión en restos esqueléticos de murciélagos (Mammalia: Chiroptera)

2018

Taphonomic studies dealing with small mammals do not usually consider bats. Therefore, the degree to which bat bones are modi? ed by predation and other taphonomic agents are largely unknown. Here we present the results obtained from a set of experiments developed to approach this issue, focusing initially on the e?ect of digestion. For this purpose several bat bones and teeth were exposed to HCl and to two di?erent proteolithic enzymes. The experiments showed that bat bones are altered by acidic and enzymatic attack in a similar way as the bones of other small mammals. However, some patterns were observed in the teeth that had not been previously described in other groups. Thus, both the i…

Functional characterization of the human tRNA methyltransferases TRMT10A and TRMT10B

2020

Abstract The TRM10 family of methyltransferases is responsible for the N1-methylation of purines at position 9 of tRNAs in Archaea and Eukarya. The human genome encodes three TRM10-type enzymes, of which only the mitochondrial TRMT10C was previously characterized in detail, whereas the functional significance of the two presumably nuclear enzymes TRMT10A and TRMT10B remained unexplained. Here we show that TRMT10A is m1G9-specific and methylates a subset of nuclear-encoded tRNAs, whilst TRMT10B is the first m1A9-specific tRNA methyltransferase found in eukaryotes and is responsible for the modification of a single nuclear-encoded tRNA. Furthermore, we show that the lack of G9 methylation cau…