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:3.4.21.1 (chymotrypsin)
10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Work from a number of laboratories has shown that fertilization is blocked in the presence of protease inhibitors, although the specific site of inhibition has not been identified. The present experiments were designed to discriminate between sperm binding to zonae pellucidae as opposed to sperm penetration through zonae, so as to assess the effect of protease inhibitors on these two distinct events. Exposure of capacitated mouse spermatozoa to a variety of protease inhibitors directed against trypsin blocked sperm binding to zonae in a concentration-dependent manner. A chymotrypsin-directed inhibitor was not capable of blocking sperm binding to zonae. The trypsin inhibitors did not affect sperm penetration though zonae nor gamete membrane fusion if the sperm had established a firm association with the zona surface before addition of the inhibitors. Previous incubation of zona-intact eggs with the inhibitors did not lead to a reduction in sperm binding, indicating that the activity affected by the inhibitors is borne by spermatozoa. Interaction between spermatozoa and the zona surface appeared to be the specific locus of inhibition; sperm binding to zona-free eggs (i.e., binding to the egg plasma membrane) was unaltered by the trypsin inhibitors. These results suggest a reevaluation of the function of proteases in fertilization focusing on their role in initial sperm contact with the zona pellucida.
...
PMID:Involvement of trypsin-like activity in binding of mouse spermatozoa to zonae pellucidae. 694 26

Boar spermatozoa were radioactively labeled by either lactoperoxidase-catalysed iodination or galactose oxidase oxidation followed by reduction with tritiated sodium borohydride. Plasma membrane glycoproteins were solubilized with the non-ionic detergent Nonidet P40 and separated by affinity chromatography on concanavalin A-Sepharose. A major water-soluble concanavalin A receptor of molecular weight greater than 160 000 was isolated by gel filtration and ion-exchange chromatography. Its amino acid and carbohydrate composition were determined. This glycoprotein is susceptible to digestion by trypsin or chymotrypsin.
...
PMID:The isolation and characterization of a concanavalin A receptor from boar spermatozoa surface. 723 91

Anti-sperm antibodies in semen have been associated with a decrease in fertility potential. The question arises as to whether intra-uterine insemination (IUI) can improve pregnancy rates by merely allowing earlier capacitation and close timing to ovulation, or whether certain treatments of the spermatozoa add extra benefit. The study presented herein was designed to compare IUI using Percoll density separation with an albumin treatment versus chymotrypsin/galactose treatment. Sixteen patients were evaluated where IUI was randomized between both sperm treatments. Pregnancy rates/cycle were 25% (eight of 32) with chymotrypsin/galactose-treated spermatozoa compared to only 3% (one of 33) cycles with albumin-treated spermatozoa (P < 0.01). Since it has been reported that the proportions of spermatozoa showing immunobead binding for specific antibodies after chymotrypsin/galactose treatment remain unchanged, the exact mechanism for improvement is unknown; possibly chymotrypsin/galactose interferes with the function of the antibodies.
...
PMID:The use of chymotrypsin/galactose to treat spermatozoa bound with anti-sperm antibodies prior to intra-uterine insemination. 800 39

A mouse monoclonal antibody against boar acrosin and antiserum prepared to highly purified acrosin in female rabbits were used to detect the antigen in various fluids and tissues of boars using an indirect immunofluorescence technique. A strong reaction was found in fluid and epithelial tissue of the seminal vesicles as well as in the germinal cells in the testis. No immunoreactivity was detected in tissues of the epididymides and other organs of the boar. The antigens present in seminal vesicle fluid of boars were partially purified by column chromatography. It was demonstrated that two antigens differing in molecular mass were present and both possessed protease and amidase activity. The higher molecular mass antigen eluted from a gel filtration column in a volume identical to that of proacrosin. The same result was obtained in polyacrylamide gel electrophoresis in sodium dodecyl sulfate (SDS-PAGE). The low molecular mass antigen was eluted from Sephadex G-75 column together with natural protease inhibitors corresponding in molecular mass to less than 20 kDa. The mobility of the antigen in SDS-PAGE was greater than that of chymotrypsin. It is assumed that the protease from seminal vesicle epithelial resembled acrosin in structure and function. Acrosin may therefore not be specific for spermatozoa.
...
PMID:Serine protease activity in boar seminal vesicles and its immunological similarity to sperm acrosin. 802 64

Because seminal plasma contains factors that inhibit the fertilizing ability of spermatozoa, it is essential that spermatozoa be separated from it quickly and efficiently. Although the success of a sperm preparation method is often assessed by the yield of motile spermatozoa, the choice of a method also depends on its technical complexity, the materials and apparatus required and time costs. Any exposure of spermatozoa during preparation to factors that may cause iatrogenic sperm dysfunction must obviously be avoided. Consequently, methods involving centrifugal washing prior to the selection of motile spermatozoa should be avoided. Direct swim-up from semen is the simplest way to obtain highly motile sperm populations and can be a very rapid procedure with normal semen samples. Two-layer discontinuous Percoll gradients give excellent yields when the lower layer contains 81% (v/v) Percoll. However, for severely asthenozoospermic cases the results can be disappointing and a Nycodenz gradient may be better, although the 'mini-Percoll' technique might be useful if special care is taken to protect the spermatozoa from damage induced by free radicals. In such cases the migration-sedimentation approach can also be successful. Abnormal samples, especially those with increased viscosity, may benefit from prior dilution with culture medium, or even chymotrypsin-induced liquefaction, before density gradient centrifugation. Finally, pharmacological stimulation of sperm motility may increase yields but, for in vitro fertilization (IVF), such spermatozoa must be used to inseminate oocytes as soon as possible after exposure to the stimulant, although after its removal.
...
PMID:Sperm recovery techniques to maximize fertilizing capacity. 806 18

The effect of chymotrypsin inhibitors and substrates on the human sperm acrosome reaction stimulated by the human zonae pellucidae or follicular fluid were evaluated. Motile spermatozoa, selected by a Percoll gradient, were incubated at 1 x 10(7) cells/ml, 37 degrees C, and 5% CO2. After 4.5 hr, the chymotrypsin inhibitor TPCK (N-Tosyl-L-Phenylalanine-Chloromethyl Ketone) or the substrate ATEE (N-Acetyl-L-Tyrosine Ethyl Ester) were added for 30 min. Then, four oocytes were added and the percentage of acrosome-reacted spermatozoa on the zona was determined. TPCK and ATEE inhibited the zona pellucida-induced acrosome reaction. The chymotrypsin inhibitors TPCK and chymostatin and the chymotrypsin substrates ATEE, BTEE (N-Benzoyl-L-Tyrosine Ethyl Ester), Succinyl-Ala-Ala-Phe-7-Amido-4-Methyl-Coumarin (Suc-Ala-Ala-Phe-AMC), and Succinyl-Leu-Leu-Val-Tyr-7-Amido-4-Methyl-Coumarin (Suc-Leu-Leu-Val-Tyr-AMC) inhibited the human follicular fluid-induced acrosome reaction. Sperm extracts exhibited hydrolytic activity toward Suc-Ala-Ala-Phe-AMC and Suc-Leu-Leu-Val-Tyr-AMC. This enzyme activity was abolished by TPCK and chymostatin, was independent of Ca2+, and was not modified by 1,10 phenanthroline. In addition, the activity was present in the supernatant after the acrosome reaction was induced with calcium ionophore and in epididymal spermatozoa recovered from the cauda region. Electron microscopic observations indicated that the inhibitors prevented the membrane events of the acrosome reaction. These data suggest an association between human spermatozoa and chymotrypsin-like activity with a possible role in the acrosome reaction.
...
PMID:Evidences for the presence of chymotrypsin-like activity in human spermatozoa with a role in the acrosome reaction. 808 Jun 52

Two sperm motility inhibitors (SMI1 and SMI2) were purified from porcine seminal plasma with high performance liquid chromatography (HPLC). Their molecular weights are about 15,000 as estimated by SDS-polyacrylamide gel electrophoresis (SDS-PAGE). Both of them decreased the percentage of motile spermatozoa in a dose-dependent manner. The inhibitory effect can be abolished by addition of the porcine follicular fluid. Both SMI1 and SMI2 have similar amino acid composition, suggesting that they may be structurally related. They also have inhibitory effect on chymotrypsin.
...
PMID:Purification and characterization of reversible sperm motility inhibitors from porcine seminal plasma. 846 Oct 1

A 78-kDa spermatozoa motility inhibiting factor (SMIF) was purified from chicken (Gallus domesticus) seminal plasma by anion exchange (DE-53) followed by affinity chromatography on concanavalin A-Sepharose. The factor is thermostable and inhibited the spermatozoa motility in a dose dependent manner. In addition, SMIF inhibited the growth of gram negative bacteria, Pasteurella multocida but not gram positive Streptococcus equi. The factor lost its spermatozoa immobilizing property after treatment with trypsin, chymotrypsin or pepsin. The inhibition of SMIF by beta-mercaptoethanol suggest the involvement of disulfide bonds in its activity. Similarly, this property was lost in presence of chicken seminal plasma or incubating SMIF with anti-SMIF antibodies. Evidence is provided for the presence of a high molecular weight protein (> 100 kDa) in chicken seminal plasma that neutralizes the motility inhibiting property of SMIF. No significant decrease in spermatozoa ATP was observed in presence of SMIF suggesting that the loss of spermatozoa motility was due to factors other than depletion in cell's energy. Using anti-SMIF antibodies, a cross-reactive protein was identified in the blood, liver and reproductive tissues of chicken and the seminal plasma of cattle and buffalo. However, the cross-reactive protein failed to inhibit chicken spermatozoa motility. The significance of SMIF in chicken seminal plasma is discussed.
...
PMID:Isolation of a spermatozoa motility inhibiting factor from chicken seminal plasma with antibacterial property. 854 20

Evidence is provided that the glycolytic enzyme glyceraldehyde 3-phosphate dehydrogenase is covalently linked to the fibrous sheath. The fibrous sheath is a typical structure of mammalian spermatozoa surrounding the axoneme in the principal piece of the flagellum. More than 90% of boar sperm glyceraldehyde 3-phosphate dehydrogenase activity is sedimented after cell disintegration by centrifugation. Detergents, different salt concentrations or short term incubation with chymotrypsin do not solubilize the enzyme, whereas digestion with trypsin or elastase does. Short term incubation with trypsin (15 minutes) even resulted in an activation of glyceraldehyde 3-phosphate dehydrogenase. Purification on phenyl-Sepharose yielded a homogeneous glyceraldehyde 3-phosphate dehydrogenase as judged from gel electrophoresis SDS-PAGE and native gradient PAGE. The molecular masses are 41.5 and 238 kDa, respectively, suggesting native glyceraldehyde 3-phosphate dehydrogenase to be a hexamer. Rabbit polyclonal antibodies raised to purified glyceraldehyde 3-phosphate dehydrogenase show a high specificity for mammalian spermatozoal glyceraldehyde 3-phosphate dehydrogenase, while other proteins of boar spermatozoa or the muscle glyceraldehyde 3-phosphate dehydrogenase are not labelled. Immunogold staining performed in a post-embedding procedure reveals the localization of glyceraldehyde 3-phosphate dehydrogenase along the fibrous sheath in spermatozoa of boar, bull, rat, stallion and man. Other structures such as the cell membrane, dense fibres, the axoneme or the mitochondria are free of label. During the process of sperm maturation, most of the cytoplasm of the sperm midpiece is removed as droplets during the passage through the epididymis. The labelling of this cytoplasm, in immature boar spermatozoa and in the droplets, indicates that glyceraldehyde 3-phosphate dehydrogenase is completely removed from the midpiece during sperm maturation in the epididymis. The inverse compartmentation of the glycolytic enzyme and mitochondria in the mammalian sperm flagella suggests that ATP-production in the principal piece mainly occurs by glycolysis and in the midpiece by respiration.
...
PMID:Glyceraldehyde 3-phosphate dehydrogenase is bound to the fibrous sheath of mammalian spermatozoa. 926 69

We purified by fractionation on 10-40% glycerol gradients, 26S proteasomes from normal human spermatozoa. These proteasomes, which participate in the ATP-dependent degradation of ubiquitinated proteins, share a similar sedimentation coefficient to those purified from other human tissues. Fluorogenic peptide assays reveal they have chymotrypsin, trypsin and peptidyl-glutamyl-like peptide hydrolysing activities; the chymotrypsin activity is ablated by the specific 26S proteasome inhibitor MG132. Confirmation that these large proteases are 26S proteasomes is provided by detection of the 20S proteasome subunits HC2, XAPC7, RN3 and Z and regulatory ATPases MSS1, TBP1, SUG1 and SUG2 by Western analyses with monoclonal antisera. These antigens are found only in the gradient fractions enriched in proteolytic activities. We have also shown that, although mature spermatozoa from mice have considerably reduced amounts of a ubiquitin-conjugating enzyme (E2) and ubiquitin-protein conjugates in comparison with less mature germ cells, they retain relatively high values of 26S proteasome activity. This suggests that proteasomes may have further roles to play in normal sperm physiology.
...
PMID:Purification and characterization of 26S proteasomes from human and mouse spermatozoa. 946 50


<< Previous 1 2 3 4 Next >>

---