Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The protease acrosin is widely considered to be an essential component of a zona lysin which enables sperm to penetrate the zona pellucida of the egg. Sperm form a characteristic penetration slit little wider than the sperm head itself and this has long suggested that any zona lysin is attached to the sperm surface after an acrosome reaction. This paper provides the first ultrastructural evidence that this is the case. The protein acrosin inhibitor, Kunitz soybean trypsin inhibitor, has been covalently attached to the electron-dense marker, ferritin, and the conjugate incubated with guinea-pig sperm which have undergone an A23187-induced acrosome reaction. Electron microscopy shows that ferritin is distributed unevenly over the outer surface of the newly exposed inner acrosomal membrane but does not extend to the equatorial segment. This is further evidence that acrosin can be considered as a candidate for the role of zona lysin. The mechanism of sperm penetration of the zona is discussed in the light of these observations.
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PMID:The histochemical localization of acrosin in guinea-pig sperm after the acrosome reaction. 35 79

Ferritin-conjugated soybean trypsin inhibitor was used for the ultrastructural localization of acrosin in bull spermatozoa following acrosomal disruption. The ferritin label was observed in the anterior segment of the acrosome in disrupted cells only. Emptied acrosomes were labeled, mostly on the external surface of their outer membrane. Labeling was also found on the material bound to detached acrosomal caps. However, at no time could the ferritin label be found on the inner acrosomal membrane. It is concluded that acrosin activity is not present on the inner acrosomal membrane but is lost from the acrosomal matrix as the acrosomal reaction proceeds.
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PMID:Acrosin does not appear to be bound to the inner acrosomal membrane of bull spermatozoa. 49 Jan 28

The efficiency of semi-dry electrophoretic transfer after sodium dodecyl sulfate (SDS)-electrophoresis using PhastGel media was investigated in a model system using three isotope labelled proteins. To give a full picture of the blotting process the amount of protein present in the gel, membranes, and filter papers was determined after different transfer times. The influence of the transfer buffer, commonly used additives such as methanol and SDS, and several different immobilizing matrices was investigated. Soybean trypsin inhibitor, bovine serum albumin, and ferritin were used as model proteins to study the effect of size on transfer efficiency. Basically, all three stages of the blotting process decide the result; the elution of protein from the gel, the immobilization of protein to the membrane, and the loss of material from the membrane during transfer. A theoretical explanation for the observed poor binding to a second membrane is discussed. Our results show that the buffer composition has little influence on the efficiency of transfer from the gel, but can be significant to the binding capacity of the membrane. In all experiments performed, there was never one moment during the transfer when all protein was eluted from the gel and simultaneously still bound to the membrane. The highest recovery in the membrane was obtained at different time intervals for different proteins. This indicates that quantitative transfer procedures cannot be generalized. However, obtaining an optimal method for reliable quantification of a specific protein or group of proteins is possible. For general protein staining of nitrocellulose and polyvinylidene difluoride membranes, a highly sensitive silver staining method requiring only 15 min has been used.
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PMID:Important parameters in semi-dry electrophoretic transfer. 169 Jun 43

In the absence of a specific marker for renal cell carcinoma (RCC), we evaluated the tumour-associated trypsin inhibitor (TATI) in patients with RCC. Between November 1990 and November 1993, 63 patients with RCC and 23 patients with benign renal disease underwent a competitive radioimmunoassay of TATI. The cutoff value was defined on a series of serum samples of 96 healthy subjects (normal n < 20 micrograms/l, then 25 micrograms/l after April 1993). We related the value of TATI to the tumour stage and compared the sensitivities of TATI and other markers (CEA, CA 15-3, CA 125, CA 19-9, ferritin). In 24 patients the TATI assay was repeated 3-12 months after radical nephrectomy. 15 patients with benign disease had a normal value of TATI (specificity: 65%). 44 of the 63 patients had a value of TATI above the cutoff point (sensitivity: 69%). Sensitivities of CEA, CA 15-3, CA 125, CA 19-9 and ferritin were 5, 10, 13, 5, 35%, respectively. The TATI value was correlated with the stage of the disease. Among the 15 patients without metastasis, the mean preoperative value was 112 micrograms/l (14-760) versus 46 micrograms/l (24-180) postoperatively. In the 9 patients with metastasis, the preoperative mean value was 100 micrograms/l (20-434) versus 240 micrograms/l (22-544) postoperatively. TATI showed a better sensitivity than other markers for RCC but its specificity is limited. Nevertheless it can be useful for a postoperative follow-up. TATI remains one of the best serum markers for RCC.
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PMID:Tumour-associated trypsin inhibitor and renal cell carcinoma. 760 Nov 86

The brain is the most compartmentalized organ. It is also highly aerobic. Because nerve cells grow but do not regenerate, the brain is the organ best suited for the accumulation of metabolic errors colocalized in specific areas of the brain over an extended period. Alzheimer's disease (AD) is primarily a neurological disorder of the elderly. It is suggested that this disorder results from the accumulation of such errors, and that AD onset aluminum and iron contribute to but do not necessarily initiate the onset of the disease. In vitro and in vivo evidence summarized here suggests that this is effected by interfering in the utilization of glucose and glucose-6-phosphate, and sequestration of iron by ferritin. beta-amyloid precusor proteins (beta-APPs) are normal components of the human brain and some other tissues. Proteolysis of these, presumably by serine proteases, generates a 39 to 42 amino acid long peptide, the alpha-amyloid (beta-AP). In AD brains, beta-AP aggregates into plaque, the hallmark of AD brains. Some of the alpha-APPs also contain a 56 amino acid long segment which inhibits serine proteases. We show that in vitro, at pH 6.5, aluminum activates beta-chymotrypsin 2-fold and makes it dramatically resistant to protease inhibitors such as bovine pancreatic trypsin inhibitor (bPTI) or its mimic present in the beta-amyloid precursor proteins (beta-APPs). Iron and oxygen are reported to favor cross-linking of beta-AP in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Iron and aluminum homeostasis in neural disorders. 784 99