scholarly journals Purification of isopenicillin N synthetase

1984 ◽  
Vol 222 (3) ◽  
pp. 789-795 ◽  
Author(s):  
C P Pang ◽  
B Chakravarti ◽  
R M Adlington ◽  
H H Ting ◽  
R L White ◽  
...  
Keyword(s):  
Streptomyces Clavuligerus ◽  
Protein Band ◽  
Maximum Activity ◽  
Polyacrylamide Gel ◽  
Major Protein ◽  
Synthetase Activity ◽  
Cephalosporium Acremonium ◽  
Major Protein Band ◽  
Isopenicillin N Synthetase ◽  
Isopenicillin N

Isopenicillin N synthetase was extracted from Cephalosporium acremonium and purified about 200-fold. The product showed one major protein band, coinciding with synthetase activity, when subjected to electrophoresis in polyacrylamide gel. An isopenicillin N synthetase from Penicillium chrysogenum was purified about 70-fold by similar procedures. The two enzymes resemble each other closely in their Mr, in their mobility on electrophoresis in polyacrylamide gel and in their requirement for Fe2+ and ascorbate for maximum activity. Preliminary experiments have shown that a similar isopenicillin N synthetase can be extracted from Streptomyces clavuligerus.

Partial purification and characterization of isopenicillin N epimerase activity from Streptomyces clavuligerus

1983 ◽  
Vol 29 (11) ◽  
pp. 1526-1531 ◽  
Author(s):  
Susan E. Jensen ◽  
Donald W. S. Westlake ◽  
Saul Wolfe
Keyword(s):  
Pyridoxal Phosphate ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Streptomyces Clavuligerus ◽  
Enzymic Activity ◽  
Partial Purification ◽  
Major Protein ◽  
Major Protein Band ◽  
Isopenicillin N

Epimerase activity, which converts isopenicillin N to penicillin N, has been partially purified from cell-free extracts of Streptomyces clavuligerus. No stimulating cofactors of this activity were found, and neither EDTA nor anaerobic incubation caused significant inhibition of activity. Although pyridoxal phosphate did not stimulate epimerase activity, the presence of this cofactor was necessary for the stabilization of enzymic activity during the purification process. Epimerase activity was purified 35.5-fold by a combination of salt precipitation, gel filtration, and ion exchange chromatography. Gel filtration indicated that the epimerase has a molecular weight of 60 000 and sodium dodecyl sulphate – polyacrylamide gel electrophoresis of the 35.5-fold purified epimerase showed a major protein band running near that location. Pyridoxal phosphate antagonists did not uniformly inhibit epimerase activity, but the inhibitory effect of hydroxylamine could be partially reversed by pyridoxal phosphate.

scholarly journals Purification and properties of pyruvate kinase from the hepatopancreas of Carcinus maenas

1976 ◽  
Vol 153 (1) ◽  
pp. 127-134 ◽  
Author(s):  
I G Giles ◽  
P C Poat ◽  
K A Munday
Keyword(s):  
Pyruvate Kinase ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Carcinus Maenas ◽  
Deae Cellulose ◽  
Protein Band ◽  
Polyacrylamide Gel ◽  
Major Protein ◽  
Major Protein Band

Pyruvatekinase from the hepatopancreas of the common shore crab, Carcinus maenas, was purified to a specific activity of 240 units/mg of protein in the assay conditions described. 2. In one method of purification the enzymic activity could be resolved into two fractions after chromatography on DEAE-cellulose. Fructose 1, 6-diphosphate was able to effect the conversion of one form (peak 1) into the second (peak 2). 3. In the presence of a saturating concentration of fructose 1, 6-diphosphate both forms of the enzyme were kinetically similar. 4. Polyacrylamide-gel electrophoresis of the enzyme 1 day after preparation showed a single protein band. On storage at least three protein bands became visible, all of which were associated with pyruvate kinase activity. 5. Chromatography of the enzyme on Sephadex G-200 indicated a mol.wt. of 247000, but in the presence of fructose 1, 6-diphosphate the elution volume of the enzyme increased corresponding to a mol.wt. of 193000. 6 Dissociation of the enzyme in sodium dodecyl sulphate and 2-mercaptoethanol followed by polyacrylamide-gel electrophoresis produced one major protein band with a mol.wt. of 55000.

Functional specificity of jejunal brush-border pteroylpolyglutamate hydrolase in pig

1991 ◽  
Vol 260 (6) ◽  
pp. G865-G872 ◽  
Author(s):  
C. J. Chandler ◽  
D. A. Harrison ◽  
C. A. Buffington ◽  
N. A. Santiago ◽  
C. H. Halsted
Keyword(s):  
Brush Border ◽  
Protein Band ◽  
Major Protein ◽  
Functional Specificity ◽  
Major Protein Band ◽  
Regional Location ◽  
Minor Protein ◽  
A Minor ◽  
Hydrolysis Of

To determine the functional specificity of intestinal brush-border pteroylpolyglutamate hydrolase (PPH), we compared the regional location of in vivo hydrolysis of pteroyltriglutamate (PteGlu3) with the location of activity and immunoreactivity of the enzyme in the pig. After in vivo incubations, PteGlu3 hydrolytic products were recovered from intestinal segments in the jejunum but not from the ileum. Brush-border PPH activity in fractionated mucosa was 10-fold greater in the jejunum than in the ileum, whereas the activity of intracellular PPH was increased in the distal ileum. Antibodies to purified brush-border PPH identified a major protein band at 120 kDa and a minor protein band at 195 kDa in solubilized jejunal brush border. Immunohistochemistry identified the enzyme only on the brush-border surface of the jejunum, whereas an immunoblot of solubilized brush-border membranes identified brush-border PPH in the jejunum but not in the ileum. The parallel of the regional location of in vivo hydrolysis of PteGlu3 with the location of brush-border PPH activity and immunoreactivity demonstrates the functional specificity of this enzyme in folate digestion.

Revised immunolocalization of the Na+-d-glucose cotransporter SGLT1 in rat organs with an improved antibody

2008 ◽  
Vol 295 (2) ◽  
pp. C475-C489 ◽  
Author(s):  
Daniela Balen ◽  
Marija Ljubojević ◽  
Davorka Breljak ◽  
Hrvoje Brzica ◽  
Vilim Z̆lender ◽  
...  
Keyword(s):  
Small Intestine ◽  
Protein Expression ◽  
Rat Kidney ◽  
Protein Band ◽  
Tissue Expression ◽  
Major Protein ◽  
Rat Organs ◽  
Major Protein Band ◽  
Outer Stripe ◽  
Intracellular Organelles

Previously, we characterized localization of Na+-glucose cotransporter SGLT1 ( Slc5a1) in the rat kidney using a polyclonal antibody against the synthetic COOH-terminal peptide of the rat protein (Sabolić I, Škarica M, Gorboulev V, Ljubojević M, Balen D, Herak-Kramberger CM, Koepsell H. Am J Physiol Renal Physiol 290: 913–926, 2006). However, the antibody gave some false-positive reactions in immunochemical studies. Using a shortened peptide for immunization, we have presently generated an improved, more specific anti-rat SGLT1 antibody (rSGLT1-ab), which in immunochemical studies with isolated membranes and tissue cryosections from male (M) and female (F) rats exhibited 1) in kidneys and small intestine, labeling of a major protein band of ∼75 kDa; 2) in kidneys of adult animals, localization of rSGLT1 to the proximal tubule (PT) brush-border membrane (S1 < S2 < S3) and intracellular organelles (S1 > S2 > S3), with zonal (cortex < outer stripe) and sex differences (M < F) in the protein expression, which correlated well with the tissue expression of its mRNA in RT-PCR studies; 3) in kidneys of castrated adult M rats, upregulation of the protein expression; 4) in kidneys of prepubertal rats, weak and sex-independent labeling of the 75-kDa protein band and immunostaining intensity; 5) in small intestine, sex-independent regional differences in protein abundance (jejunum > duodenum = ileum); and 6) thus far unrecognized localization of the transporter in cortical thick ascending limbs of Henle and macula densa in kidney, bile ducts in liver, enteroendocrine cells and myenteric plexus in the small intestine, and initial ducts in the submandibular gland. Our improved rSGLT1-ab may be used to identify novel sites of SGLT1 localization and thus unravel additional physiological functions of this transporter in rat organs.

scholarly journals Biochemical studies on the activity of δ-(l-α-aminoadipyl)-l-cysteinyl-d-valine synthetase from Streptomyces clavuligerus

1992 ◽  
Vol 283 (3) ◽  
pp. 691-698 ◽  
Author(s):  
J Zhang ◽  
S Wolfe ◽  
A L Demain
Keyword(s):  
Enzyme Activity ◽  
High Temperature ◽  
Bioactive Compounds ◽  
Streptomyces Clavuligerus ◽  
Synthetase Activity ◽  
Enzyme Specificity ◽  
Acidic Ph ◽  
Reaction Parameters ◽  
Biochemical Studies ◽  
Isopenicillin N

The enzyme activity of purified delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine (ACV) synthetase from Streptomyces clavuligerus was studied biochemically. The dependence of ACV synthetase activity on reaction parameters, including substrates, cofactors, temperature and pH, were determined, resulting in a substantially increased enzyme activity. The activity is very labile to high temperature and is also unstable at acidic pH. The enzyme specificity is strict towards L-alpha-aminoadipate, but rather loose with respect to L-valine; certain modifications of L-cysteine can also be tolerated. Some unnatural tripeptides synthesized by ACV synthetase can be converted into bioactive compounds by isopenicillin N synthase. The only nutrient found to negatively affect ACV synthetase activity is phosphate, but various compounds such as thiol-blocking reagents and ATP-utilization products (AMP and pyrophosphate) are inhibitory to the enzyme.

Studies on the ring-cyclization and ring-expansion enzymes of β-lactam biosynthesis in Cephalosporium acremonium

1983 ◽  
Vol 29 (5) ◽  
pp. 488-496 ◽  
Author(s):  
Jutta Kupka ◽  
Yong-Qiang Shen ◽  
Saul Wolfe ◽  
Arnold L. Demain
Keyword(s):  
Micrococcus Luteus ◽  
Gel Filtration ◽  
Ring Expansion ◽  
Exchange Chromatography ◽  
Cephalosporium Acremonium ◽  
Competitive Inhibitors ◽  
Isopenicillin N Synthetase ◽  
Soluble Enzymes ◽  
Temperature Optima ◽  
Isopenicillin N

Micrococcus luteus was found to be very sensitive to isopenicillin N and was used as assay organism for purification of the enzyme isopenicillin N synthetase, which cyclizes δ-(L-α-aminoadipyl)-L-cysteinyl-D-valine to isopenicillin N. Purification of the enzyme from the crude extract obtained by sonication of mycelia of Cephalosporium acremonium CW-19 was carried out by ammonium sulfate precipitation, desalting with Sephadex G-25, gel filtration on LKB ultrogel AcA44 or ion-exchange chromatography on DEAE-Sepharose. The cyclization enzyme was separated from the ring-expansion enzyme and was purified considerably more than 50-fold by this procedure. Using the purified enzyme, we found that the disulfide bis-δ-(L-α-aminoadipyl)-L-cysteinyl-D-valine required reduction to δ-(L-α-aminoadipyl)-L-cysteinyl-D-valine in order to behave as a substrate. The enzyme activity was stimulated by FeSO4 and ascorbate, but other cofactors, including α-ketoglutarate, were inactive. In addition to δ-(L-α-aminoadipyl)-L-cysteinyl-D-valine, the enzyme converted adipyl-L-cysteinyl-D-valine, N-acetyl-δ-(L-α-aminoadipyl)-L-cysteinyl-D-valine, and glycyl-δ-(L-α-aminoadipyl) L-cysteinyl-D-valine to penicillins. All of these latter peptides were competitive inhibitors of the cyclization reaction. The Km of the cyclization enzyme is 10 times higher than that of the ring-expansion enzyme, deactoxycephalosporin C synthetase. The pH and temperature optima of the two enzymes were rather similar. Phosphate inhibited ring expansion, but not cyclization. Both enzymes appear to be soluble enzymes of about 31 000 molecular weight.

scholarly journals Chronic lymphocytic leukemia antibodies with a common stereotypic rearrangement recognize nonmuscle myosin heavy chain IIA

Blood ◽  
2008 ◽  
Vol 112 (13) ◽  
pp. 5122-5129 ◽  
Author(s):  
Charles C. Chu ◽  
Rosa Catera ◽  
Katerina Hatzi ◽  
Xiao-Jie Yan ◽  
Lu Zhang ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Protein Band ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Major Protein ◽  
Nonmuscle Myosin ◽  
Cell Extracts ◽  
Major Protein Band

Abstract Leukemic B lymphocytes of a large group of unrelated chronic lymphocytic leukemia (CLL) patients express an unmutated heavy chain immunoglobulin variable (V) region encoded by IGHV1-69, IGHD3-16, and IGHJ3 with nearly identical heavy and light chain complementarity-determining region 3 sequences. The likelihood that these patients developed CLL clones with identical antibody V regions randomly is highly improbable and suggests selection by a common antigen. Monoclonal antibodies (mAbs) from this stereotypic subset strongly bind cytoplasmic structures in HEp-2 cells. Therefore, HEp-2 cell extracts were immunoprecipitated with recombinant stereotypic subset-specific CLL mAbs, revealing a major protein band at approximately 225 kDa that was identified by mass spectrometry as nonmuscle myosin heavy chain IIA (MYHIIA). Reactivity of the stereotypic mAbs with MYHIIA was confirmed by Western blot and immunofluorescence colocalization with anti-MYHIIA antibody. Treatments that alter MYHIIA amounts and cytoplasmic localization resulted in a corresponding change in binding to these mAbs. The appearance of MYHIIA on the surface of cells undergoing stress or apoptosis suggests that CLL mAb may generally bind molecules exposed as a consequence of these events. Binding of CLL mAb to MYHIIA could promote the development, survival, and expansion of these leukemic cells.

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