Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A protein, present in bovine seminal plasma, initiates forward motility in immature, immotile caput spermatozoa that have been incubated with a cyclic AMP phosphodiesterase inhibitor. An improved motility assay was developed to study this process and the protein involved. This forward motility protein exhibits multiple forms when fractionated on the basis of charge or molecular weight. Molecular sieving in urea or sodium dodecyl sulfate and dithiothreitol results in a single peak of activity which will re-form the larger aggregates in the absence of these agents. The molecular weight of this monomeric motility protein, as estimated from molecular sieving under these dissociating conditions, is 37,500. The forward motility protein can be partially purified by heat treatment, gell chromatography in urea, and affinity chromatography on concanavalin A/agarose. Enzymatic treatments further suggest a glycoprotein nature, i.e. treatment with beta-galactosidase, neuraminidase, alpha-mannosidase, or galactose oxidase reduces its activity by 50%; treatment with trypsin completely abolishes forward motility protein activity. On the basis of concurrent studies on the activity, properties, and distribution of forward motility protein in bovine body fluids, it is suggested that this protein is involved in the development of the capacity for motility as sperm traverse the epididymis.
...
PMID:Bovine sperm forward motility protein. Partial purification and characterization. 21 Nov 30

Intact spermatozoa from rat cauda epididymis possess a Mg2+-dependent ATPase activity that hydrolyses externally added [gamma-32P]ATP. The ATPase reaction was linear with time for approx. 6 min and there was no detectable uptake of ATP by these cells. The ATPase activity of the whole spermatozoa was not due to leakage of the intracellular enzymic activity, contamination of the broken cells or any possible cell damage during incubation and isolation of spermatozoa. The activity of the enzyme was strongly inhibited (approx. 85%) by p-chloromercuribenzenesulphonic acid (50 microM) or the diazonium salt of sulphanilic acid (50 microM), which are believed not to enter the cells, whereas ouabain (0.5 mM), NaF (10 mM), NaN3 (2.5 mM) and oligomycin (5 microM) had no appreciable effect on the activity of the spermatozoal APTase. There was little loss of ATPase activity from the cells when washed with 0.5 mM-EDTA and an iso-osmotic or hyperosmotic medium. These data are consistent with the view that the observed ATPase activity is located on the external surface of spermatozoa. The sperm ecto-ATPase activity is resistant to the action of proteinases (50 micrograms/ml), namely trypsin, chymotrypsin and Pronase. Studies with various unlabelled phosphate esters indicate that the sperm ecto-ATPase is not a non-specific phosphatase and it has high degree of substrate specificity for ATP.
...
PMID:Evidence for the occurrence of an ecto-(adenosine triphosphatase) in rat epididymal spermatozoa. 23 71

The size of androgen receptors from rat ventral and dorsal prostate, dorsal prostate (Dunning) tumor, testis, epididymis, and seminal vesicle was determined using Sephadex G-200 chromatogrpahy and sucrose gradient centrifugation. The protease inhibitor diisopropyl fluorophosphate (DFP) was used to minimize receptor breakdown. An 8-9 S, 85 to 106 A receptor (Mr = 280,000 to 365,000; f/fo = 1.9 to 2.4) observed in unfractionated cytosol prepared in low ionic strength buffer with or without DFP is in equilibrium with a 4.5-5 S, 58 A form (Mr = 117,000; f/fo = 1.8) observed at salt concentrations greater than 0.1 M KCl. Receptor partially purified using (NH4)2SO4 or phosphocellulose chromatography in the absence of DFP was present as smaller fragments of 3.6 S, 37 A and 3.0 S, 23 A. Similar fragments could be generated from the 4.5 S or 8 S receptor by mild trypsin treatment. In addition, ventral prostate contains a DFP-insensitive enzyme which specifically converts the 4.5 S, 58 A receptor to the 3.6 S 37 A fragment. The DFP-insensitive enzyme is partially inhibited by rabbit bile and appears similar to the enzyme seminin, a secretory protein of human prostate. Androgen receptor isolated in the presence of DFP from nuclei labeled in vivo is predominantly 4.5 S, 58 A, with smaller forms (37 and 23 A) appearing in the absence of DFP. The 4.5 S, 58 A nuclear receptors were also in equilibrium with a large 8 S form. Receptor breakdown by DFP-insensitive and sensitive proteases appears to be an in vitro phenomenon. Furthermore, the size of the androgen receptor is not significantly changed during receptor migration from cytoplasm to nucleus.
...
PMID:Effects of proteases and protease inhibitors on the 4.5 S and 8 S androgen receptor. 44 15

Acrosome of human sperm possesses two distinct antigens that are immunogenic, and will elicit autoantibodies that are detectable by immunofluorescence (IF). The first antigen, Acl, diffuse in distribution, is probably glycoprotein in nature since it is removed by trypsin and periodate. It is readily removed from cells after incubation in acid buffer or phosphate-buffered saline (PBS), stable at 60 degrees C and not affected by trypsin inhibitor. The second antigen, Ac2, discrete in distribution, is resistant to trypsin treatment. It remains stable after incubation in acid buffer or PBS, is unstable at 60 degrees C and becomes more diffuse in distribution when incubated in acid buffer or trypsin inhibitor. The use of spermatozoa pretreated with acid buffer permits detection of anti-Ac2 antibody that coexists with anti-Ac1 antibody in the same serum sample. Both Ac1 and Ac2 antigens are demonstrable in spermatozoa from the ejaculate, epididymis and the testis; in spermatids and spermatocytes. Ac1 antigen appears to show extensive cross-reaction with micro-organisms and with antigen(s) of human adrenal gland; and anti-Ac1 antibody is found frequently in the serum of men before vasectomy. In contrast, Ac2 antigen does not show cross-reaction with micro-organisms or tissue antigens tested; and its antibody is found mainly in the male and primarily after vasectomy. Thus, anti-Ac2 antibody may be more indicative of an immune response to sperm, and should be sought in diseases related to sperm immunity.
...
PMID:Human sperm antigens and antisperm antibodies. III. Studies on acrosomal antigens. 127 79

A specific 135-kDa protein was purified from porcine cauda epididymal fluid. Analysis of its N-terminal amino acid sequence revealed it to be a new protein. Stable clones of hybridomas that produced monoclonal antibodies against the purified 135-kDa protein were established. A clone, B-11, reacting both with epididymal fluid and with sperm plasma membranes was selected and used in this study. Immunoblotting analysis showed that B-11 reacted only with a 135-kDa protein among epididymal fluid proteins. In contrast, B-11 did not recognize a similar 135-kDa sperm protein but did strongly react with a 27-kDa protein among sperm membrane proteins, extracted by NP-40 in the presence of protease inhibitors. B-11 also reacted only with a 27-kDa protein fragment among trypsin digests of the 135-kDa epididymal protein. The 135-kDa protein was first detected, by ELISA or immunoblotting analysis, at the beginning of the corpus epididymis. Maximal levels were reached in the distal corpus and levels were slightly decreased in the cauda epididymis. On the other hand, the surface of caput sperm were found to contain small amounts of antigen(s), the concentration of which gradually increased during epididymal transit. In immunocytochemical studies, the antigen was detectable in the epithelial cells from the initial segment to the corpus of the epididymis but not in the caudal cells. In the lumen, the presence of the 135 kDa protein was apparent in the corpus (at a maximum in the middle and distal corpus) and to a lesser degree in the caudal lumen. The 27-kDa protein was distributed all over the equatorial region of the acrosome of less than 10% of caput epididymal sperm. As sperm passed through the corpus epididymis, the percentage of immunoreactive cells increased and the protein was restricted to specific domains of the sperm head. Thus, on the mature sperm, antigen was localized in a crescent-shaped area of the equatorial segment just behind the anterior part of the acrosome and on the apical rim of the sperm head. This is the first observation of a sperm surface antigen derived from an epididymal protein as a proteolytic fragment that interacts with specific regions of the sperm membrane during the process of spermatozoa maturation.
...
PMID:Localization of a maturation-dependent epididymal sperm surface antigen recognized by a monoclonal antibody raised against a 135-kilodalton protein in porcine epididymal fluid. 149 68

Several studies suggest that acrosin, an acrosomal trypsin-like serine proteinase, plays a role in fertilization. The enzyme is present in an enzymatically inactive precursor form, called proacrosin and is believed to be converted to the enzymatically active form(s) through one/multiple physiological event(s) prior to the sperm penetration of the zona pellucida. Although, the proacrosin-acrosin system of several species has been well documented, the study of the enzyme system in bovine caput and cauda epididymis (where the maturation of spermatozoa occurs) has not been characterized. The present study demonstrates the quantification and partial characterization of the proacrosin-acrosin proteinase system in unpurified acrosomal extracts of bovine caput and cauda epididymal sperm. Proacrosin activation followed the sigmoidal type of activation curve. Activation experiments demonstrate that almost 80-90% of this protein exists in zymogen (proacrosin) form either in ejaculated or caput and cauda epididymal spermatozoa. Time-course activation studies showed that the zymogen in isolated spermatozoa was completely converted to active non-zymogen form in 3 and 5 h after removal from the cauda and caput regions, respectively, at pH 8.0 at 25 degrees C. This conversion was markedly inhibited by calcium in a dose dependent manner and the inhibition was reversible. On the other hand, calcium has a stimulatory effect on the hydrolytic activity of acrosin. These studies reveal that the proacrosin-acrosin system can be identified in crude extracts of bull epididymal and ejaculated sperm.
...
PMID:Bovine epididymal sperm proacrosin-acrosin system: quantification and partial characterization. 150 54

A hybridoma (3B2-F7) has been established which secretes a monoclonal antibody (Mab) directed against a peptide determinant of human seminal plasma glycoprotein (HSP-gP). The deglycosylation of HSP-gP was performed chemically with TFMS hydrolysis and enzymatically in the presence of detergent and further treated with periodic acid after fixing deglycosylated HSP on plastic wells. The Mab 3B2-F7 (IgM, kappa) exhibited sperm immobilization activity (256 units of SI50) and inhibited sperm binding to human zona pellucida. Human epididymis, pancreatic islets of Langerhan's and distal tubulus of kidney were strongly labelled whilst other tissues were essentially negative by avidin-biotin complex tissue staining with this Mab. The antigen epitope to the Mab was in the 36 kDa molecule of human HSP-gP. The antigenic determinant recognized by Mab 3B2-F7 was destroyed by six different proteases, but was resistant to N-glycanase and other carbohydrate splitting enzymes. This epitope is therefore likely to be composed of a polypeptide chain. Peptide fragments after proteolysis of the HSP molecule with Staph. aureus V8 protease and trypsin retained antigenicity, hence the epitope corresponding to the Mab may be a peptide chain and not dependent on the conformational structure of the polypeptide.
...
PMID:Monoclonal antibody recognizing an apparent peptide epitope of human seminal plasma glycoprotein and exhibiting sperm immobilizing activity. 169 87

We have studied the binding of [125I-iodo]androgen-binding protein (ABP) and of [3H]delta 6-testosterone photoaffinity-labelled ABP to receptors in the plasma membrane of rat epididymal cells in three ways: ABP binding to a Triton X-100-solubilized membrane extract, ABP binding to isolated epithelial cells in suspension and autoradiography of segments of dissected epididymides after in-vitro intraluminal injection of labelled ABP. The binding of iodinated ABP to the receptor was similar to that of photoaffinity-labelled ABP in gel filtration. The ABP-receptor complex was eluted from Superose 6 gels as an aggregate, with a molecular mass of 2000 kDa. It was separated into two peaks by sucrose gradient ultracentrifugation, with respective sedimentation coefficients of 18.4 and 9.0 s. The activity of the receptor (ABP-binding capacity/mg protein) was tenfold higher in the caput than in the cauda. The binding of ABP to the receptor was pH dependent, being almost abolished at pH less than 4. The binding at 4 degrees C of photoaffinity-labelled ABP to epithelial cells corresponded to two types of binding sites. The numbers of high-affinity and low-affinity sites per cell were 1600 and 7700 respectively; the association constants of these sites were 67.9 and 2.8 litres/nM respectively. The binding was decreased by treatment of the cells with trypsin or incubation in the presence of EDTA. The binding in vitro of labelled ABP to the epididymis epithelium reached a maximum after about 20 min at 4 degrees C. In the autoradiographic study the tracer was found to be closely associated with coated pits, coated vesicles, endosomes and pale multivesicular bodies. Treatment of rats with cycloheximide significantly reduced the uptake of the tracer. Perfusion in vitro of epididymides with chloroquine produced a fourfold increase of the tracer in endosomes and multivesicular bodies.
...
PMID:Evidence that androgen-binding protein endocytosis in vitro is receptor mediated in principal cells of the rat epididymis. 193 Jun 25

Due to the central role the acrosomal region plays in sperm-egg interactions, monoclonal antibodies (mAbs) were used to identify components of this domain in mouse sperm. Several sperm proteins that localize specifically to the anterior acrosomal region are described here in terms of electrophoretic mobility, susceptibility to proteolytic degradation, and post-translational modification during epididymal transit. Six different mAbs were used, each recognizing a distinctive antigen (Ag) or set of Ags in cauda epididymal mouse sperm: a doublet of 185/200 Kd (M42 mAb); 150-160 Kd (M5 mAb); 105 Kd (W71 mAb); 21, 35, and 60 Kd (M41 mAb); 27 and 33 Kd (W33 mAb); and 57 and 86 Kd (W108 mAb). Previously reported work implicates two of these, M42 Ag and M5 Ag, as participants in sperm-zona interaction (Saling and Lakoski: Biol Reprod 33:527-536, 1985; Saling: Dev Biol 117:511-519, 1986; and Lakoski et al.: Biol Reprod 38:221-233, 1988). Recognition of some (M42, M5, W108), but not all (W33), of the Ags by their corresponding mAbs was affected by sperm incubation with proteases (trypsin or collagenase). Evidence of post-translational modification during epididymal maturation was suggested by altered electrophoretic mobility of several of the Ags (M42, M5, W33, and W108) accompanying sperm transit from proximal to distal epididymis. Retention of sperm within the caput epididymis prevented structural alterations for the four proteins examined, indicating that spatial rather than temporal factors are critical for Ag modification in maturing mouse sperm.
...
PMID:Proteins of the acrosomal region in mouse sperm: immunological probes reveal post-testicular modifications. 254 83

The effect of vitamin E deficiency on levels of proteinase inhibitors in sex glands of male rats was studied. Inhibitor levels against cysteine proteinases, such as ficin and cathepsin H, and against serine proteinase such as trypsin were examined. Vitamin E deficiency for 4 mo after weaning induced a fivefold increase in cysteine proteinase inhibitor level in testis, a two- to fourfold increase in prostate and epididymis and no change in seminal vesicle. No appreciable change was observed in trypsin inhibitor level in testis, epididymis or seminal vesicle. Therefore, vitamin E deficiency was reflected most sensitively by the cysteine proteinase inhibitor level in testis. These observations agree with our previous findings that alpha-cysteine proteinase inhibitors in serum increased greatly whereas trypsin inhibitor in serum did not change in vitamin E-deficient rats. Major histological changes were observed in the testes of rats fed a vitamin E-deficient diet for 4 mo, although testis weight was not significantly affected by vitamin E deficiency.
...
PMID:Enhancement of testicular cysteine proteinase inhibitor level in vitamin E-deficient rats. 349 20


1 2 3 4 Next >>

---