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Theoretical Molecular Weight (theoretical + molecular_weight)

Distribution by Scientific Domains

Polymers and Materials Science	50%

Selected Abstracts

Molecular cloning of CYP1A gene and its expression by benzo(a)pyrene from goldfish (Carassius auratus)

ENVIRONMENTAL TOXICOLOGY, Issue 3 2009
Seung-Min Oh
Abstract We cloned and sequenced the cytochrome P450 1A (CYP1A) gene from goldfish (Carassius auratus). It has a 1581 bp open reading frame that encodes a 526 amino acid protein with a theoretical molecular weight of 59.02 kDa. The CYP1A amino acid sequence clusters in a monophyletic group with other fish CYP1As, and more closely related to zebrafish CYP1A (91% identity) than to other fish CYP1As. Exposure to benzo(a)pyrene (BaP) by intraperitoneal injection increased biliary BaP metabolites and liver CYP1A gene expression. BaP exposure also increased CYP1A gene expression in extrahepatic organs, including intestine, and gill, which are sensitive to aqueous and dietary exposure to Arylhydrocarbon receptor (AhR) agonists. Therefore, goldfish CYP1A identified in this study offers basic information for further research related to biomarker use of CYP1A of goldfish. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2009. [source]

Mammalian reovirus core protein,µ2 initiates at the first start codon and is acetylated

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 24 2002
Magdalena I. Swanson
Mammalian reovirus is an enteric virus that contains a double-stranded RNA genome. The genome consists of ten RNA segments that encode eight structural and three non-structural proteins. The structural proteins form a double-layered structure. The innermost layer, called the core, consists of five proteins (,1, ,2, ,3, µ2, and ,2). Protein ,3 is the RNA-dependent RNA polymerase (RdRp) and µ2 is thought to be an RdRp cofactor. Translation of most reovirus proteins is known to commence at the first start codon. However, the translation initiation site of the viral core protein,µ2, encoded by the M1 RNA segment, has been in dispute. Although the theoretical molecular weight of µ2 is 83 267,Da the actual molecular weight is unknown because,µ2 runs aberrantly in SDS-PAGE and has resisted characterization by Edman degradation, indicating that the amino terminus is post-translationally modified. In this study, we used proteolysis coupled with MALDI-Qq-TOFMS to determine that translation of µ2 initiates at the first AUG codon, that its actual molecular weight approximates the theoretical value of 83,kDa, that the amino terminal methionine residue is removed, and that the next amino acid (alanine) is post-translationally acetylated. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Synthesis of block copolymers by combined ultrasonic irradiation and reverse atom transfer radical polymerization processes

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 3 2004
Mustafa Degirmenci
Abstract A two-step procedure based on ultrasonic irradiation and reverse atom transfer radical polymerization (RATRP) for the synthesis of block copolymers is described. In the first step of the procedure, a stable chlorine-end-capped polymer is formed upon the ultrasonic irradiation of poly(methyl methacrylate) (PMMA) in dry benzene in the presence of a copper chloride/2,2,-bipyridine catalyst. Heating the system to 110 °C initiates the polymerization of the second monomer, styrene, and this results in the formation of the block copolymers. The degradation behavior of PMMA under ultrasonic irradiation has also been studied. The agreement of the experimentally obtained molecular weights and theoretical molecular weights and the unimodal shapes of the gel permeation chromatography curves of the block copolymers indicate the controlled nature of the RATRP process initiated by polymeric radicals formed by sonication. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 534,540, 2004 [source]

Nonstoichiometric polycondensation I. synthesis of polythioether from dibromomethane and 4,4,-thiobisbenzenethiol

MACROMOLECULAR SYMPOSIA, Issue 1 2003
Hirokazu Iimori
Abstract High molecular weight poly(phenylene thioether) (3) was successfully obtained by the polycondensation of 4,4,-thiobisbenzenethiol (1) and dibromomethane (2) with a variety of feed ratios in the presence of 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU) in 1-methyl-2-pyrrolidinone (NMP) at 75°C. The resulting polymer showed the maximum inherent viscosity (,inh) of 0.50 dL/g in 4 h when 1.5 equivalents excess of 2 was used. The model reaction using benzenethiol (4) and dichloromethane (5) in the presence of DBU in deuterated dimethylsulfoxide (DMSO- d6) at 25°C indicated that the rate of the second nucleophilic displacement reaction (k2) is 61 times faster than that of the first one (k1). The maximum of theoretical molecular weights calculated at various stoichiometric imbalance (S) under the condition of k2/k1 = 61 showed a good agreement with the experimental molecular weights at specific polymerization times. [source]