scholarly journals Oestrogen induction of riboflavin-binding protein in immature chicks. Nature of the secretory protein

1978 ◽  
Vol 170 (2) ◽  
pp. 331-335 ◽  
Author(s):  
U S Murthy ◽  
P R Adiga
Keyword(s):  
Binding Protein ◽  
Molecular Size ◽  
Egg Yolk ◽  
Secretory Protein ◽  
Yolk Protein ◽  
Chicken Liver ◽  
Yolk Proteins ◽  
Treated Male

The riboflavin-binding protein isolated from sera of oestrogen-treated male chicks as well as that synthesized and secreted in vitro by the chicken liver have the same molecular size as that of the egg-yolk protein. Functionally the serum and yolk proteins are similar. This is in contrast with the hormone-induced synthesis, secretion and deposition of phosvitin and lipovitellin in the ovary.

Major secretory protein of human decidualized endometrium in pregnancy is an insulin-like growth factor-binding protein

1988 ◽  
Vol 118 (2) ◽  
pp. 317-328 ◽  
Author(s):  
S. C. Bell ◽  
S. R. Patel ◽  
J. A. Jackson ◽  
G. T. Waites
Keyword(s):  
Growth Factor ◽  
Amniotic Fluid ◽  
Incubation Medium ◽  
Binding Protein ◽  
Secretory Protein ◽  
Insulin Like Growth Factor ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein

ABSTRACT Pregnancy-associated endometrial α1-globulin (α1-PEG) is quantitatively the major secretory protein product, synthesized and secreted in vitro, of the human decidualized endometrium during pregnancy. This protein has been purified from cytosolic extracts of this tissue and has now been characterized as a 32 kDa somatomedin/insulin-like growth factor (IGF)-binding protein. Immunoreactive α1-PEG isolated from amniotic fluid exhibited identical physiochemical properties and IGF-I-binding characteristics. In cytosolic extracts of pregnancy endometrium, in incubation medium of this tissue and in amniotic fluid, the 32 kDa protein represented the major α1-PEG immunoreactive protein and major IGF-I-binding component. Purified α1-PEG and incubation medium of pregnancy endometrium competed for IGF-I with placental membrane IGF receptors in vitro. The implications of the endometrial source of IGF-I-binding protein are dicussed with reference to the origin of the amniotic fluid and serum small Mr IGF-binding protein and to the suggested paracrine effect upon trophoblast proliferation. J. Endocr. (1988) 118, 317–328

Formation of Transport Coated Pits and Vesicles Uniquely Stimulated by Exogenous Yolk Proteins in in vitro Oocytes

1971 ◽  
Vol 29 ◽  
pp. 396-397
Author(s):  
Thomas F. Roth ◽  
John Dodson ◽  
Barbara Boss
Keyword(s):  
Active Transport ◽  
Blood Meal ◽  
Specific Protein ◽  
Yolk Protein ◽  
Model Systems ◽  
Coated Pits ◽  
Yolk Proteins ◽  
Morphological Basis ◽  
Saturation Kinetics

We have characterized several systems that exhibit selective protein sequestration in order to use them as model systems to elucidate the mechanisms of specific protein endocytosis. One of these, the mosquito ovary, is ideal because it contains synchronous oocytes and is easily cultivated in vitro. To date we have characterized the yolk proteins, established that the oocytes selectively sequester yolk proteins and that the oocytes effectively exclude other proteins. The transport exhibits saturation kinetics typical of active transport and is inhibitable.To establish the morphological basis of this selection, we incubated ovaries that had been previously active in laying down yolk (24 hr post blood meal) in an in vitro culture with either yolk protein, ferritin, IgG, albumin, or a combination of these proteins. We confirmed earlier observations that significant transport occurs only in the presence of yolk proteins.

scholarly journals s-cyclophilin is retained intracellularly via a unique COOH-terminal sequence and colocalizes with the calcium storage protein calreticulin.

1992 ◽  
Vol 116 (1) ◽  
pp. 113-125 ◽  
Author(s):  
S Arber ◽  
K H Krause ◽  
P Caroni
Keyword(s):  
Intracellular Transport ◽  
Cultured Cells ◽  
Signal Sequence ◽  
Binding Protein ◽  
Secretory Protein ◽  
Storage Site ◽  
Terminal Sequence ◽  
Peptide Bonds ◽  
Site Markers

Cyclophilins (cyclosporin A-binding proteins) are conserved, ubiquitous, and abundant proteins that accelerate the isomerization of XaaPro peptide bonds and the refolding of proteins in vitro. s-Cyclophilin is a member of the cyclophilin family with unique NH2- and COOH-terminal extensions, and with a signal sequence. We now report that s-cyclophilin is retained in the cell, and that the conserved s-cyclophilin-specific COOH-terminal extension VEKPFAIAKE is sufficient to direct a secretory protein to s-cyclophilin containing structures. Antibodies to s-cyclophilin-specific peptides were produced and the location of the protein was determined by an immunocytochemical study at the light microscopic level. s-Cyclophilin colocalized with the Ca(2+)-binding protein calreticulin and, to a lesser extent, with the microsomal Ca(2+)-ATPase in the myogenic cell line L6, and with the Ca(2+)-binding protein calsequestrin in skeletal muscle. In activated platelets, s-cyclophilin immunoreactivity was detected in a ring-like structure that might correspond to the Ca(2+)-storing and -releasing dense tubular network. In spreading cells, s-cyclophilin containing vesicular structures accumulated at actin-rich protrusion sites. While s-cyclophilin consistently codistributed with Ca2+ storage site markers, the distribution of s-cyclophilin immunoreactivity was not identical to that of ER markers. To determine whether the COOH-terminal extension of s-cyclophilin was involved in its intracellular transport we added this sequence to the COOH-terminus of the secretory protein glia-derived nexin. Appropriate constructs were expressed transiently in cultured cells and proteins were detected with specific antibodies. We found that glia-derived nexin with the COOH-terminal sequence VEKPFAIAKE (but not with the control sequence GLVVMNIT) colocalized with endogenous s-cyclophilin, indicating that the sequence contained retention information. These results indicate that s-cyclophilin is a retained component of an intracellular organelle and that it may accumulate in specialized portions of the ER, and possibly in calciosomes. Because of its conserved structure, widespread distribution, and abundance s-cyclophilin may be a useful marker to study the biogenesis and distribution of ER subcompartments.

scholarly journals Formation of a functional ribosome-membrane junction during translocation requires the participation of a GTP-binding protein.

1986 ◽  
Vol 103 (6) ◽  
pp. 2253-2261 ◽  
Author(s):  
T Connolly ◽  
R Gilmore
Keyword(s):  
Signal Sequence ◽  
Binding Protein ◽  
Signal Recognition Particle ◽  
Secretory Protein ◽  
Signal Recognition ◽  
Gtp Binding Protein ◽  
Gtp Binding ◽  
Protease Digestion ◽  
Nascent Chain

The requirement for ribonucleotides and ribonucleotide hydrolysis was examined at several distinct points during translocation of a secretory protein across the endoplasmic reticulum. We monitored binding of in vitro-assembled polysomes to microsomal membranes after removal of ATP and GTP. Ribonucleotides were not required for the initial low salt-insensitive attachment of the ribosome to the membrane. However, without ribonucleotides the nascent secretory chains were sensitive to protease digestion and were readily extracted from the membrane with either EDTA or 0.5 M KOAc. In contrast, nascent chains resisted extraction with either EDTA or 0.5 M KOAc and were insensitive to protease digestion after addition of GTP or nonhydrolyzable GTP analogues. Translocation of the nascent secretory polypeptide was detected only when ribosome binding was conducted in the presence of GTP. Thus, translocation-competent binding of the ribosome to the membrane requires the participation of a novel GTP-binding protein in addition to the signal recognition particle and the signal recognition particle receptor. The second event we examined was translocation and processing of a truncated secretory polypeptide. Membrane-bound polysomes bearing an 86-residue nascent chain were generated by translation of a truncated preprolactin mRNA. Ribonucleotide-independent translocation of the polypeptide was detected by cleavage of the 30-residue signal sequence after puromycin termination. Nascent chain transport, per se, is apparently dependent upon neither ribonucleotide hydrolysis nor continued elongation of the polypeptide once a functional ribosome-membrane junction has been established.

scholarly journals Interaction of the anti-oestrogen, nafoxidine hydrochloride, with the soluble nuclear oestradiol-binding protein in chick liver

1977 ◽  
Vol 164 (3) ◽  
pp. 659-667 ◽  
Author(s):  
C B Lazier ◽  
W S Alford
Keyword(s):  
Binding Protein ◽  
Sedimentation Coefficient ◽  
Egg Yolk ◽  
Binding Activity ◽  
Receptor Interaction ◽  
Usual Model ◽  
Nuclear Extracts ◽  
Liver Nuclei

Nafoxidine hydrochloride (Upjohn, 11100A)injected with oestradiol into immature chicks inhibits the hormone-induced increase in [3H]oestradiol-binding activity in salt extracts of liver nuclei as well as the subsequent production by liver of egg-yolk phosphoprotein. Substantial inhibition of both oestradiol-induced responses is seen when nafoxidine is given in a dose approximately equimolar with that of oestradiol. In vitro nafoxidine competitively inhibits binding of [3H]oestradiol in nuclear extracts. The Ki for the inhibition is 43 nM, which indicates an affinity of nafoxidine for the binding protein about 4% of that of oestradiol. The inhibitory action of nafoxidine in vivo thus is more potent than the relative binding affinity determined in vitro might indicate. One possible explanation is that the primary site of nafoxidine action is at a point proximal to nuclear receptor interaction. Nafoxidine injected alone into the chick does not induce phosphoprotein synthesis, but it does increase [3H]oestradiol-binding activity in extracts of liver nuclei to a limited extent. No differences in the properties of the oestradiol-binding activity in extracts from nafoxidine-treated chicks or from oestradiol-treated chicks were detected. Chick liver cytosol does not contain detectable high-affinity oestradiol-binding activity. A low-affinity oestradiol-binding component with a sedimentation coefficient of 3.5S was found, but it was unaffected by treatment of chicks with earlier nafoxidine or oestradiol. The results suggest a difference in the mechanism of oestradiol action in the chick liver and in the widely studied rat uterus, on which the usual model for oestradiol action is largely based.

Horse plasma corticotrophin-releasing hormone (CRH): characterisation and lack of a late gestational rise or a plasma CRH-binding protein

1994 ◽  
Vol 143 (3) ◽  
pp. 455-460 ◽  
Author(s):  
M J Ellis ◽  
J H Livesey ◽  
R A Donald
Keyword(s):  
Peripheral Blood ◽  
Binding Protein ◽  
Molecular Size ◽  
Binding Activity ◽  
Late Gestation ◽  
Releasing Hormone ◽  
Methanolic Extracts ◽  
Equine Plasma ◽  
Venous Plasma

Abstract Immunoreactive corticotrophin-releasing hormone (irCRH) was present in methanolic extracts of equine peripheral blood and showed no elevation in maternal peripheral serum in late gestation (0·54 ±0·25 pmol/l; mean ± s.d.) compared with control horses (0·41 ± 015 pmol/l). The irCRH of methanolic extracts of pituitary venous plasma had a similar elution position following reverse-phase HPLC to synthetic human CRH(1–41) and to irCRH released from horse stalk-median eminence tissue incubated in vitro. Gel chromatographic studies showed no evidence for a plasma CRH-binding protein (CRHBP) analogous to that found in human plasma in either peripheral blood from normal or pregnant horses or in pituitary venous plasma sampled from a cannulated horse. CRH-binding activity was detectable in peripheral plasma from one horse, however the molecular size of this was indicative of a γ-globulin rather than the 37 kDa CRHBP. These studies suggest that, unlike in the human, CRH does not rise to high values in late gestation nor circulate in a bound form in equine plasma. Journal of Endocrinology (1994) 143, 455–460

Evaluation of Snake Venom’s PhospholipaseA2 Enzyme Inhibition Activity of Cyphostemma adenocoule

2020 ◽  
Vol 14 (3) ◽  
pp. 196-202
Author(s):  
Atul Kaushik ◽  
Teamrat S. Tesfai ◽  
Daniel K. Barkh ◽  
Furtuna K. Ghebremeskel ◽  
Habtom G. Zerihun ◽  
...  
Keyword(s):  
Enzyme Inhibition ◽  
Snake Venom ◽  
Ethanol Extract ◽  
Egg Yolk ◽  
Chloroform Extract ◽  
Inhibition Activity ◽  
Traditional Use ◽  
Snake Bites ◽  
Ethanol Extracts

Background: A snake bite is fundamentally an injury often resulting in puncture wounds meted out by the animal's fangs and occasionally resulting in envenomation. Rate of snake bites around 5,400,000 bites per year leads to over 2,500,000 envenomings and around 125,000 fatal cases annually. Snake venom enzymes are rich in metalloproteinases, phospholipaseA2, proteinases, acetylcholinesterases and hyaluronidases. Objective: Cyphostemma adenocoule is traditionally being used for the treatment of snake bites in Eritrea. The present research was aimed at evaluating the snake venom enzyme inhibition activity of C. adenocoule against puff adder venom and developing a base for the traditional use of the plant against snakebites in Eritrea. Methods: The anti-venom activity of C. adenocoule was assessed in-vitro through phospholipaseA2 enzyme inhibition assay using egg yolk as a cell. The ethanol and chloroform extracts of C. adenocoule showed in vitro anti phospholipase A2 activity, whereas the water extracts of the plant showed no activity. Results: Among the extracts of C. adenocoule, the highest percentage of inhibition was obtained from chloroform extract (95.55% at 100mg/ml). The extract showed prominent activity at different concentrations (34.7% at10mg/ml, 48.8% at 20mg/ml, 54.8% at 40mg/ml, 60.9% at 60mg/ml, 80.5% at 80mg /ml). The ethanol extract also showed certain activity at various concentrations (25.22% at10mg/ml, 14.78% at 20mg/ml, 2.6% at40mg/ml). The activity of the chloroform extracts increases as concentration increases, whereas the activity of the ethanol extracts decreases as concentration increases. The aqueous extract of C. adenocoule did not show any activity at all concentrations. Conclusion: In this study, the chloroform and ethanol extracts of the plant inhibited the enzyme of interest and thus proved the efficacy of anti-snake venom activity of the plant.

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