scholarly journals Glycyl-l-leucine hydrolase, a versatile ‘master’ dipeptidase from monkey small intestine

1973 ◽  
Vol 135 (4) ◽  
pp. 609-615 ◽  
Author(s):  
Manjusri Das ◽  
A. N. Radhakrishnan
Keyword(s):  
Molecular Weight ◽  
Chromatographic Method ◽  
Gel Filtration ◽  
Peptide Transport ◽  
Small Intestinal Mucosa ◽  
Highly Active ◽  
Structural Types ◽  
Wide Range ◽  
Small Intestinal

1. A highly active and electrophoretically homogeneous dipeptidase was purified from the soluble extracts of monkey small-intestinal mucosa. 2. By gel-filtration studies the molecular weight of the enzyme was found to be 107000. It is composed of two identical, subunits of molecular weight 54000. 3. A paper-chromatographic method of dipeptidase assay was developed to overcome some of the difficulties encountered in the generally used spectrophotometric procedure. By using this method, the Km and k0 values of a few substrates were determined. 4. The substrate specificity of the enzyme was investigated in great detail with substrates of a wide range of possible structural types. The enzyme hydrolyses a very large proportion of the range of dipeptides tested. This enzyme, which exhibits such a wide range of action, has been termed the ‘master’ dipeptidase of the intestine. Glycylglycine, glycyl-l-proline, glycyl-l-histidine, l-prolylglycine and some of the arginine- and aspartic acid-containing dipeptides were not substrates and are possibly hydrolysed by other peptidases. These results therefore suggest that in the intestine the number of dipeptidases is rather limited. 5. In the light of these findings, the implications on the role of dipeptidases in intestinal peptide transport are discussed.

scholarly journals A chromatographic preparation of ox growth hormone

1966 ◽  
Vol 100 (3) ◽  
pp. 593-600 ◽  
Author(s):  
M Wallis ◽  
HBF Dixon
Keyword(s):  
Molecular Weight ◽  
Growth Hormone ◽  
Gel Electrophoresis ◽  
Anterior Pituitary ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Starch Gel Electrophoresis ◽  
Highly Active ◽  
Cross Linkage ◽  
Starch Gel

1. A method is described for the chromatographic preparation of ox growth hormone. It involves chromatography of an extract of anterior pituitary lobes on DEAE-cellulose, followed by rechromatography on a dextran gel of low cross-linkage (Sephadex G-100). 2. The product is highly active in growth-hormone assays, and is obtained in good yield. It was homogeneous by several criteria, but showed some heterogeneity on starch-gel electrophoresis. 3. The molecular weight of the hormone was estimated from its behaviour on gel-filtration columns under various conditions. Evidence that the hormone may dissociate into sub-units under some conditions is presented.

scholarly journals The essential role of physiotherapists in providing rehabilitation services to people living with HIV in South Africa

2013 ◽  
Vol 69 (1) ◽  
Author(s):  
S. Cobbing ◽  
V. Chetty ◽  
J. Hanass-Hancock ◽  
J. Jelsma ◽  
H. Myezwa ◽  
...  
Keyword(s):  
South Africa ◽  
South African ◽  
Policy Formulation ◽  
People Living With Hiv ◽  
Highly Active ◽  
Hiv Epidemic ◽  
Wide Range ◽  
Living With Hiv ◽  
Education Courses

Despite increased access to highly active anti-retroviral therapy (HAART) in South Africa, there remains a high risk of people living with HIV (PLHIV) developing a wide range of disabilities. Physiotherapists are trained to rehabilitate individuals with the disabilities related to HIV. Not only can South African physiotherapists play a significant role in improving the lives of PLHIV, but by responding proactively to the HIV epidemic they can reinforce the relevance and value of the profession in this country at a time when many newly qualified therapists are unable to secure employment. This paper offers recommendations that may help to fuel this response. These ideas include enhancing HIV curricula at a tertiary level, designing and attending continuing education courses on HIV and researching Southern African rehabilitation interventions for HIV at all levels of practice. furthermore, it is vital that physiotherapists are at the forefront of directing multi-disciplinary responses to the rehabilitation of PLHIV in order to influence stakeholders who are responsible for health policy formulation. it is hoped that this paper stimulates discussion and further ideas amongst physiotherapists and other health professionals in order to improve the quality and access to care available to PLHIV in South Africa.

Acid proteases from species of Mucor. III. Interaction with concanavalin A and concanavalin A Sepharose

1976 ◽  
Vol 54 (2) ◽  
pp. 120-129 ◽  
Author(s):  
W. S. Rickert ◽  
P. A. McBride-Warren
Keyword(s):  
Molecular Weight ◽  
Concanavalin A ◽  
Gel Filtration ◽  
Apparent Molecular Weight ◽  
Affinity Column ◽  
Mucor Miehei ◽  
Highly Active ◽  
Elution Buffer ◽  
Turbidimetric Assay ◽  
Ph Range

The reaction of Mucor miehei protease with concanavalin A was followed by a turbidimetric assay in the pH range 5–8. At pH 4.0, no turbidity developed but binding of the enzyme to concanavalin A could be demonstrated by gel filtration. Two fractions of apparent molecular weight 65 000 and 52 000 were isolated, the 65 000 molecular weight species apparently representing a protomer of concanavalin A (24 000) bound to the enzyme. An analysis of the circular dichroism spectrum of this complex suggested that protomer binding results in a conformational change in the enzyme which is associated with a 30% increase in proteolytic activity.At pH 6.0, the enzyme was strongly bound to columns of concanavalin A Sepharose but could be removed by including α-methyl D-glucoside and NaCl in the elution buffer. Some column degradation occurred at room temperature but was not detectable at 4 °C where rapid elution of the enzyme resulted in a greater than 90% yield of highly active protein. Periodate-oxidized Mucor miehei protease and Mucor rennin did not react with concanavalin A and were not bound to the affinity column.

scholarly journals Role of serum IgA. Hepatobiliary transport of circulating antigen.

1981 ◽  
Vol 153 (4) ◽  
pp. 968-976 ◽  
Author(s):  
M W Russell ◽  
T A Brown ◽  
J Mestecky
Keyword(s):  
Molecular Weight ◽  
Human Serum Albumin ◽  
Gel Filtration ◽  
Low Molecular Weight ◽  
Serum Iga ◽  
Circulating Antigen ◽  
Circulating Antigens ◽  
Iga Antibody ◽  
Immune Spleen Cell

The IgA mediated hepatobiliary excretion of antigen from the circulation was studied using a radiolabeled haptenated protein (dinitrophenyl-human serum albumin) injected intravenously in mice together with monoclonal anti-dinitrophenyl antibodies of different immunoglobulin classes. Antibodies were obtained from ascitic fluids of mice bearing the MOPC315 myeloma (IgA), or immune spleen cell hybridomas (IgG and IgM). IgA antibody brought about the transport of large amounts of antigen from the circulation to the bile during 1-3h. Analysis of bile by gel filtration showed that a large part of the transported antigen remained intact and complexed with IgA. Neither IgA of different specificity nor anti-dinitrophenyl IgM medicated biliary transport of antigen. With anti-dinitrophenyl IgG, only small amounts of low molecular weight fragments of labeled antigen were found in he bile. Preformed immune complex of radiolabeled antigen and IgA antibody were rapidly transported from the circulation to the bile, resulting in threefold-higher levels of radioactivity in bile than in serum. It is proposed that an important function of serum IgA is to mediate the hepatobiliary excretion of corresponding circulating antigens.

scholarly journals Enteral arginase II provides ornithine for citrulline synthesis

2011 ◽  
Vol 300 (1) ◽  
pp. E188-E194 ◽  
Author(s):  
Juan C. Marini ◽  
Bettina Keller ◽  
Inka Cajo Didelija ◽  
Leticia Castillo ◽  
Brendan Lee
Keyword(s):  
Small Intestine ◽  
Stable Isotope ◽  
Transgenic Mice ◽  
Small Intestinal Mucosa ◽  
Wild Type ◽  
Proline Utilization ◽  
Small Intestinal ◽  
Arginase Ii ◽  
Citrulline Synthesis

The synthesis of citrulline from arginine in the small intestine depends on the provision of ornithine. To test the hypothesis that arginase II plays a central role in the supply of ornithine for citrulline synthesis, the contribution of dietary arginine, glutamine, and proline was determined by utilizing multitracer stable isotope protocols in arginase II knockout (AII−/−) and wild-type (WT) mice. The lack of arginase II resulted in a lower citrulline rate of appearance (121 vs. 137 μmol·kg−1·h−1) due to a reduced availability of ornithine; ornithine supplementation was able to restore the rate of citrulline production in AII−/− to levels comparable with WT mice. There were significant differences in the utilization of dietary citrulline precursors. The contribution of dietary arginine to the synthesis of citrulline was reduced from 45 to 10 μmol·kg−1·h−1 due to the lack of arginase II. No enteral utilization of arginine was observed in AII−/− mice (WT = 25 μmol·kg−1·h−1), and the contribution of dietary arginine through plasma ornithine was reduced in the transgenic mice (20 vs. 13 μmol·kg−1·h−1). Dietary glutamine and proline utilization were greater in AII−/− than in WT mice (20 vs. 13 and 1.4 vs. 3.7 μmol·kg−1·h−1, respectively). Most of the contribution of glutamine and proline was enteral rather than through plasma ornithine. The arginase isoform present in the small intestinal mucosa has the role of providing ornithine for citrulline synthesis. The lack of arginase II results in a greater contribution of plasma ornithine and dietary glutamine and proline to the synthesis of citrulline.

Purification and preliminary characterization of 2-monoacylglycerol acyltransferase from rat intestinal villus cells

1985 ◽  
Vol 63 (5) ◽  
pp. 341-347 ◽  
Author(s):  
F. Manganaro ◽  
A. Kuksis
Keyword(s):  
Specific Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Cell Protein ◽  
Racemic Mixture ◽  
Small Intestinal Mucosa ◽  
Small Intestinal ◽  
Monoacylglycerol Acyltransferase

We have purified the monoacylglycerol acyltransferase from rat small intestinal mucosa to homogeneity by a combination of hydrophobic absorption, guanidine dissociation, and gel filtration. The purified enzyme gives a single band of 37 000 daltons on sodium dodecyl sulphate – polyacrylamide gel electrophoresis. The enzyme has a specific activity of about 5900 nmol/mg per hour and represents 0.12% of total cell protein, corresponding to about a 600-fold purification. The enzyme does not acylate diacylglycerols to triacylglycerols, which is consistent with the separate physical existence of the mono- and di-acylglycerol acyltransferases. The enzyme acylates the 2-monoacylglycerols to yield an essentially racemic mixture of diacylglycerols. It does not acylate glycerol 3-phosphate.

CCK-5: sequence analysis of a small cholecystokinin from canine brain and intestine

1987 ◽  
Vol 252 (2) ◽  
pp. G272-G275 ◽  
Author(s):  
J. Shively ◽  
J. R. Reeve ◽  
V. E. Eysselein ◽  
C. Ben-Avram ◽  
S. R. Vigna ◽  
...  
Keyword(s):  
High Performance ◽  
Gel Filtration ◽  
Physiological Role ◽  
Gel Permeation Chromatography ◽  
Small Intestinal Mucosa ◽  
Cck Receptors ◽  
Amino Terminal ◽  
Specific Radioimmunoassay ◽  
Carboxyl Terminal ◽  
Small Intestinal

The purpose of this study is to purify and to characterize chemically cholecystokinin (CCK)-like peptides present in brain and gut extracts that elute from gel filtration after the octapeptide. Canine small intestinal mucosa and brain were boiled in water and then extracted in cold trifluoroacetic acid, and cholecystokinin-like immunoreactivity was determined by carboxyl-terminal specific radioimmunoassay. Gel permeation chromatography on Sephadex G-50 revealed a form of CCK apparently smaller than CCK-8. This peptide was purified by immunoaffinity chromatography and three successive reverse phase high-performance liquid chromatography steps. Microsequence analysis showed that the amino terminal primary sequence of this small CCK was Gly-Trp-Met-Asp. Immunochemical and chromatographic analysis indicated that the carboxyl-terminal residue was Phe-NH2 and thus the full sequence is Gly-Trp-Met-Asp-Phe-NH2. An antibody that recognizes synthetic CCK-8, CCK-5, and CCK-4 equally did not reveal the presence of significant amounts of CCK-4. These results indicate that CCK-5 is the major CCK form smaller than the octapeptide present in brain (19% of total CCK immunoreactivity) and small intestine (7% of total). This finding, coupled with the demonstration by others that CCK-5 interacts with high-affinity brain CCK receptors, indicates that CCK-5 may play a physiological role in brain function.

scholarly journals Accumulation of malto-oligosaccharides in the syncytiotrophoblastic cells of first-trimester human placentas

1981 ◽  
Vol 200 (1) ◽  
pp. 93-98 ◽  
Author(s):  
S J Fisher ◽  
R A Laine
Keyword(s):  
Gel Filtration ◽  
First Trimester ◽  
Structural Elements ◽  
Trophoblastic Cells ◽  
Highly Active ◽  
A Cell ◽  
Liver Homogenates ◽  
High Concentrations ◽  
Very High

A cell-surface microvillar fraction that was isolated from the syncytiotrophoblastic cells of first-trimester human placentas was found to contain very high concentrations (890 +/- 32 microgram of hexose/mg of protein) of a class of low-molecular-weight oligosaccharides that were comprised entirely of glucose. T.l.c. and gel filtration showed that the saccharides contained from one to six glucose residues. The structures of the most prominent members of the series, a tetra- and a tri-saccharide, were determined. The anomeric configuration of the glucose residues was alpha, and methylation linkage analysis gave terminal and 4-linked hexose residues. These malto-oligosaccharides contained one reducing terminus per molecule, indicating that they were free and not bound to other structural elements of the cells. Within the placenta they appeared to be concentrated in the first-trimester trophoblastic cells, since crude membrane and particulate fractions isolated from either term trophoblastic cells or cultured placental fibroblasts did not contain detectable amounts of glucose oligomers. This series of oligosaccharides was similar to the products that are formed when glycogen is degraded by alpha-amylase in liver homogenates and may be indicative of a similar, highly active enzymic reaction closely associated with the brush border of the syncytiotrophoblastic cells of the first-trimester human placenta. Although the role of these oligosaccharides remains obscure they are probably involved in foetal metabolism.

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