Abstract：
:The variation with pH of the kinetic parameters of penicillin acylase from Kluyvera citrophila has been used to gain information about the chemical mechanism of the reaction catalysed by the enzyme. The pH-dependence of log (V/Km) for penicillin G showed that a group with a pK value over 4.7 must be deprotonated and that a group with a pK value over 9.7 must be protonated in the free enzyme for activity. The solvent perturbation and temperature studies indicated that these groups are respectively of cationic and neutral acid type with ionization enthalpies of 29.7 and 111 kJ/mol. It was proved that penicillin G sulphoxide is a reversible linear competitive inhibitor with respect to the hydrolysis of penicillin G. The similarity of the pH profile and the magnitude of the pK values derived from the dissociation constant, Ki, suggest that both groups are concerned with the binding of penicillin G and its analogues to the enzyme. It is proposed that binding of substrate involves the formation of hydrogen bonds between the substrate and the essential ionizable groups in the enzyme which lie within the hydrophobic environment of the active site of penicillin acylase. This suggestion is supported by the finding that the profile of V (Vmax.) is similar to the V/Km profile, except that the low and high pK values are respectively shifted downward and upward due to the entry of substrate. Moreover, the bell shape of the V profile indicated that they are also essential in the catalytic steps subsequent to binding.
journal_name
Biotechnol Appl Biochemjournal_title
Biotechnology and applied biochemistryauthors
Martín J,Prieto I,Mancheño JM,Barbero JL,Arche Rsubject
Has Abstractpub_date
1993-06-01 00:00:00pages
311-25issue
3eissn
0885-4513issn
1470-8744journal_volume
17pub_type
杂志文章abstract：:The structural underpinnings of O₂ activation in P450s have been limited by the inability to trap unstable oxy complexes in the crystalline state for structure determination. To date there are only two known oxy P450 structures. Even so, much is known about O₂ activation in P450cam and the role that redox partner bind...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章,评审
doi：10.1002/bab.1056
更新日期：2013-01-01 00:00:00
abstract：:The gene (lacS) encoding a thermostable beta-galactosidase enzyme (Ss beta-gal) from the archaebacterium Sulfolobus solfataricus has been cloned and expressed in simian CV1 and murine NIH3T3 cell lines. The recombinant protein is an active enzyme that shows the same properties of thermophilicity and thermostability as...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：
更新日期：1994-04-01 00:00:00
abstract：:Two different enzymes that metabolize lactate in the presence of oxygen, either to acetate plus CO2 (lactate 2-mono-oxygenase; Lmox) or to pyruvate plus H2O2 (lactate oxidase; Lox) were encapsulated in human and murine red blood cells (RBCs). Lmox shows a low affinity for lactate (Km 22 mM) and thus works at a low rat...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：
更新日期：1995-12-01 00:00:00
abstract：:Glycoprotein D (gD2) is the most important candidate antigen for herpes simplex virus type 2 (HSV-2) vaccine development. Establishment of a stable eukaryotic cell line to overexpress gD2 and an efficient purification process to purify is essential for the development of subunit vaccine against HSV-2. The DNA sequence...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：10.1002/bab.1386
更新日期：2016-05-01 00:00:00
abstract：:Green fluorescent protein (GFP) is a globular protein used as biosensor and biomarker in medical and industrial fields. However, due to the expensive production costs of expressing proteins using high-cost inducers like isopropyl-β-d-1-thiogalactopyranoside (IPTG), the number of GFP applications are still scarce. This...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：10.1002/bab.1749
更新日期：2019-07-01 00:00:00
abstract：:The hybridization of the native and chemically inactivated aspartase from Escherichia coli was studied. Preparations of the tetrameric enzyme obtained by mixing the native and N-ethylmaleimide (NEM)-inactivated aspartase in 4 M guanidine-HCl followed by 51-fold dilution at room temperature retained catalytic activity....
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：
更新日期：1990-04-01 00:00:00
abstract：:The phosphatase and tensin homolog (PTEN) gene plays a crucial role in signal transduction by negatively regulating the PI3K signaling pathway. It is the most frequent mutated gene in many human-related cancers. Considering its critical role, a functional analysis of missense mutations of PTEN gene was undertaken in t...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：10.1002/bab.1483
更新日期：2017-09-01 00:00:00
abstract：:High yields of extracellular alpha-galactosidase from fungal cultures were obtained by inducing enzyme production with guar gum (a galactomannan obtained from the seeds of Cyamopsis tetragonobola) as the sole carbon source. An alpha-galactosidase was isolated from the culture medium of Penicillium ochrochloron culture...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：
更新日期：1993-06-01 00:00:00
abstract：:The optimum fermentation conditions for the production of cellulose by a newly isolated Acetobacter sp. A9 were determined by shaken cultures. The strain was able to produce cellulose at 25-30 degrees C with a maximum at 30 degrees C. Cellulose production occurred at pH 4.5-7.5 with a maximum at pH 6.5. The improved m...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：10.1042/ba20000065
更新日期：2001-02-01 00:00:00
abstract：:Single base mismatched oligonucleotides related to the rpoB gene of Mycobacterium tuberculosis, the mutations of which cause drug resistance of the infectious agent, were detected and discriminated using a surface plasmon resonance biosensor system. Thiol-modified oligonucleotides of the selected sequence (the probe) ...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：10.1002/bab.1101
更新日期：2013-07-01 00:00:00
abstract：:Lys and Leu were generally considered as the key amino acids for brewer's yeast during beer brewing. In the present study, peptide Lys-Leu and a free amino acid (FAA) mixture of Lys and Leu (Lys + Leu) were supplemented in 24 °P wort to examine their effects on physiological activity and fermentation performance of br...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：10.1002/bab.1634
更新日期：2018-07-01 00:00:00
abstract：:The combination of IL-2 (interleukin-2) and GM-CSF (granulocyte/macrophage colony-stimulating factor) has been broadly studied in antitumour immune therapy, but its efficacy is uncertain. To better exert the activities of the two cytokines and study them in a mouse model, we have constructed a bifunctional protein, hI...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：10.1042/BA20070125
更新日期：2008-05-01 00:00:00
abstract：:Bioreactor process changes can have a profound effect on the yield and quality of biotechnology products. Mannose-6-phosphate (M6P) glycan content and the enzymatic catalytic kinetic parameters are critical quality attributes (CQAs) of many therapeutic enzymes used to treat lysosomal storage diseases (LSDs). Here, we ...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：10.1002/bab.1151
更新日期：2014-03-01 00:00:00
abstract：:In order to impart an ability for receptor-independent transmembrane transfer to water-soluble proteins, it has been suggested that they be hydrophobized by lipid groups (fatty acids, etc.). To this end, systems of reversed micelles of surfactants in organic solvents were used as reaction media for protein modificatio...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：
更新日期：1990-02-01 00:00:00
abstract：:Production of His-BbST [hexahistidine-tagged BbST (bubaline somatotropin)] by auto-induction in high-density shake-flask cultures coupled with a single-step, on-column purification and refolding strategy is described here. To optimize expression of BbST, different media and expression conditions were tested. The highe...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：10.1042/BA20060154
更新日期：2007-05-01 00:00:00
abstract：:The use of the recombinant BoNT/A-Hc (carboxylic domain of the Clostridium botulinum neurotoxin heavy chain) has been proposed as a vaccine candidate for botulism. This fragment contains the principle protective antigenic determinant. In the present study, in order to maximize recombinant protein expression, after ver...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：10.1042/BA20090315
更新日期：2010-05-24 00:00:00
abstract：:A novel iron superoxide dismutase (Fe-SOD) gene from Jatropha curcas was cloned and expressed in Escherichia coli BL21 (DE3). This recombinant enzyme was isolated by a combined procedure involving immobilized metal-ion affinity chromatography and ion-exchange chromatography. The apparent molecular mass of this purifie...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：10.1002/bab.1030
更新日期：2012-09-01 00:00:00
abstract：:The participation of Mg2+ or Mn2+ nucleoside diphosphates in the reverse reaction catalyzed by purified carbamate kinase (ATP:carbamate phosphotransferase, EC 2.7.2.2) of Lactobacillus buchneri NCDO110 was studied. The results of initial velocity studies have indicated that Mn2+ ADP is as effective as a substrate as M...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：
更新日期：1987-04-01 00:00:00
abstract：:The efficient enzyme-catalysed reaction of morpholines as model structures for bioactive compounds with para-dihydroxylated aromatic systems was carried out using the oxidoreductase laccase and atmospheric oxygen to produce eight novel morpholine-substituted aromatics. The laccase of Myceliophthora thermophila was use...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：10.1042/BA20090219
更新日期：2009-11-13 00:00:00
abstract：:A decrease in the specific activity of an enzyme is commonly observed when the enzyme is inappropriately handled or is stored over an extended period. Here, we reported a functional transition of an FMN-bound diaphorase (FMN-DI) that happened during the long-term storage process. It was found that FMN-DI did not simpl...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：10.1002/bab.1607
更新日期：2018-05-01 00:00:00
abstract：:Human urokinase was immobilized on an ethylene vinyl acetate copolymer surface. Soluble urokinase showed its maximum activity at pH 8.5, while the immobilized enzyme was most active at pH 9.0. Apparently, the shift in optimal pH was due to the polyanionic nature of the carrier surface on which the enzyme was immobiliz...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：
更新日期：1988-06-01 00:00:00
abstract：:Some epidemiological studies have suggested possible associations between exposure to extremely low-frequency electromagnetic fields (ELF-EMFs) and various diseases. Recently, ELF-EMF has been considered as a therapeutic agent. To support ELF-EMF use in regenerative medicine, in particular in the treatment of skin inj...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：10.1002/bab.1495
更新日期：2017-05-01 00:00:00
abstract：:We tested a variety of liposomes for parameters such as DNA binding capacity and DNase I protection of incorporated and attached DNA to elucidate their use as vehicles for DNA transfer into cells and animals. The results were compared to other potential DNA vehicles, empty viral capsids, and nanoparticles. Maximal bin...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：
更新日期：1991-06-01 00:00:00
abstract：:Bacillus subtilis strain DM-03, which is isolated from starter culture used for the production of alcohol by local Assam tribes, grows optimally at 52-55 degrees C and secretes a significant amount of alpha-amylase at pH 8.0 into the culture media. This alpha-amylase, purified by ion-exchange, gel-filtration and rever...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：10.1042/BA20040034
更新日期：2004-12-01 00:00:00
abstract：:Bovine serum albumin (BSA) microspheres with an average diameter of 12.5 micron were prepared by crosslinking of BSA molecules with glutaraldehyde in the presence of polymethylmethacrylate dissolved in chloroform-toluene. Trypsin and anti-human IgG antibody were immobilized onto their surfaces by the glutaraldehyde-ac...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：
更新日期：1988-02-01 00:00:00
abstract：:Renewable energy resources are considered to be promising for the development of a sustainable circular economy. Among various alternatives, the microbial route for various biofuels production is quite lucrative. Use of cellulose and lignocellulose for methane, H2 , organic acids, ethanol, and cellulase has been explo...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章,评审
doi：10.1002/bab.1720
更新日期：2019-03-01 00:00:00
abstract：:The human placenta is a rich raw material for production of many biopharmaceutical products. Here we describe a co-purification process for the production of four different proteins from haemolysed human placenta blood: IgG, catalase (Cat), superoxide dismutase (Sod) and albumin (Alb). The process can be divided in tw...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：10.1042/ba20010023
更新日期：2001-12-01 00:00:00
abstract：:Limit of detection (LOD), limit of quantification, and the dynamic range of detection of hepatitis B surface antigen antibody (anti-HBs) using a surface plasmon resonance (SPR) chip-based approach with Pichia pastoris-derived recombinant hepatitis B surface antigen (HBsAg) as recognition element were established throu...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：10.1002/bab.1528
更新日期：2017-09-01 00:00:00
abstract：:The purpose of the present study was to investigate the effects of garlic (Allium sativum L.) on the diabetic nephropathy and oxidative stress induced by STZ (streptozotocin) in rats. Diabetes was induced in Male Sprague-Dawley rats by administering a single intraperitoneal injection of STZ (60 mg/kg of body weight). ...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：10.1042/BA20080086
更新日期：2009-03-01 00:00:00
abstract：:The membranotropic properties of block co-polymers and their protein conjugates were studied by their effect on the rate of oxygen consumption by isolated liver mitochondria and on thymus-derived lymphocytes. The block co-polymers consisted of poly(ethylene oxide) (PoE) [poly(ethylene glycol)] and poly(propylene oxide...
journal_title：Biotechnology and applied biochemistry
pub_type： 杂志文章
doi：
更新日期：1993-12-01 00:00:00
