Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.108 (TAT)
 2,389 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A new HLA-B18 allele (B*1802) derived from a Thai individual was sequenced. Comparison of this B18 nucleotide sequence with the published B*1801 sequence indicated that this Asian B18 allele has a nucleotide sequence different from that of B*1801. Three nucleotide changes were observed in exon 3, in which two substitutions at codon 97, AGG in B*1801 to AAT in the B*1802, result in an amino acid change from arginine to asparagine. The residue 97Asn has also been described in some B27 subtypes. A silent mutation was also observed at codon 99, TAC in B*1801 to TAT in the B*1802. This sequence has been reported in many class I alleles published so far. Moreover, 18 HLA-B18-positive samples were examined by the PCR-SSO method using specific probes for B*1801 and B*1802. The results demonstrated that three Asian samples possess B*1802 and share HLA-Cw7, DR12, and DQ7.
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PMID:A new B18 sequence (B*1802) from Asian individuals. 775 Nov 57

The complete androgen insensitivity syndrome (AIS) is a sub-type of X-linked male pseudohermaphroditism resulting from total dysfunction of the androgen receptor. Affected patients are phenotypically female despite a 46,XY genotype; gonadal tissue displays a classic Sertoli cell-only pattern on microscopic examination. We describe the diagnosis and management of a 19(1/2)-year-old patient who presented for primary amenorrhea and absent cervix, identified incidentally during a routine Pap test. Serum total testosterone was elevated (725 ng/dl) and the karyotype was 46,XY. Molecular investigation for specific gene defect(s) causing disruption and functional incapacity of the androgen receptor was undertaken for the proband and her only sibling. From this we discovered a previously unknown hemizygous mutation (A-->T) in exon 4 of the androgen receptor gene, associated with replacement of asparagine (AAT) with tyrosine (TAT) in the resultant androgen receptor protein [N705Y]. Bidirectional, non-isotopic sequence analysis of exon 4 was next undertaken for the proband's sister who was found to be heterozygous for this mutation. Psychological and genetic counseling was provided to both individuals; the patient underwent an outpatient laparoscopic orchiectomy without complication. She continues to receive oral hormone replacement therapy following an oral contraceptive model. In this report, the clinical approach to AIS is outlined from a reproductive endocrinology perspective with special emphasis on psychological counseling and laboratory methods employed to confirm the diagnosis at the molecular level. We also outline other recently described mutations of the androgen receptor gene (Xq11-12) which have been associated with AIS.
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PMID:Characterization of a novel receptor mutation A-->T at exon 4 in complete androgen insensitivity syndrome and a carrier sibling via bidirectional polymorphism sequence analysis. 1174 94

Asparaginase (ASNase) is an enzyme drug presently approved for the induction of remission in the treatment of patients with acute lymphoblastic leukemia (ALL). The cytotoxic effect of ASNase is derived from its ability to deplete asparagine, an essential amino acid required by certain types of leukemia cells for protein synthesis and survival. Despite its efficacy in enhancing disease remission rate and prolonging complete remission duration in ALL patients, ASNase therapy is nevertheless confounded by a number of serious toxic effects, particularly to organs associated with high protein production (e.g., liver, pancreas), due to the systemic depletion of asparagine. Presented herein is a modified version of our previously established ATTEMPTS protein delivery system that carries the potential to permit a tumor specific, intracellular delivery of ASNase, thereby allowing for a significant reduction of ASNase-induced systemic toxicity. In a previous paper, we already demonstrated the in vitro feasibility of this heparin/protamine-regulated, TAT-mediated system in delivering ASNase directly into ASNase-sensitive murine lymphoma cells. In this article, we further validated the in vivo applicability of this system in animals harboring ASNase-encapsulated L5178Y lymphoma cells. Preliminary results showed that animals inoculated with L5178Y cells containing TAT-ASNase exhibited an extended survival rate of approximately 13% over those harboring L5178Y cells without the encapsulation of ASNase. Furthermore, the TAT-ASNase-treated mice also displayed a significantly improved hematological and liver histological status than the control groups. These findings bring promise to the use of the modified ATTEMPTS delivery system in achieving enhanced ASNase therapy.
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PMID:Preliminary in vivo evaluation of the protein transduction domain-modified ATTEMPTS approach in enhancing asparaginase therapy. 1881 76

Specific targeting and cellular internalization are key properties for carriers of antitumor therapeutic agents. Here, we develop a drug carrier through the attachment of substrate of endoprotease legumain, alanine-alanine-asparagine (AAN), to cell-penetrating peptides (TAT, trans-activating factor). The addition of the AAN moiety to the fourth lysine in the TAT creates a branched peptide moiety, which leads to a decrease in the transmembrane transport capacity of TAT by 72.65%. Legumain efficiently catalyses the release of TAT-liposome from the AAN-TAT-liposome and thereby recovers the penetrating capacity of TAT. Doxorubicin carried by the AAN-TAT-liposome led to an increase in the tumoricidal effect of doxorubicin and a reduction in its systemic adverse effects in comparison with doxorubicin carried by a control delivery system. Thus, the specific targeting and high efficiency of this delivery platform offers a novel approach to limit the toxicity of anticancer agents as well as increasing their efficacy in cancer therapy.
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PMID:Legumain protease-activated TAT-liposome cargo for targeting tumours and their microenvironment. 2496 88

Clostridium difficile TcdB (2366 amino acid residues) is an intracellular bacterial toxin that binds to cells and enters the cytosol where it glucosylates small GTPases. In the current study, we examined a putative cell entry region of TcdB (amino acid residues 1753-1851) for short sequences that function as cell-penetrating peptides (CPPs). To screen for TcdB-derived CPPs, a panel of synthetic peptides was tested for the ability to enhance transferrin (Tf) association with cells. Four candidate CPPs were discovered, and further study on one peptide (PepB2) pinpointed an asparagine residue necessary for CPP activity. PepB2 mediated the cell entry of a wide variety of molecules including dextran, streptavidin, microspheres, and lentivirus particles. Of note, this uptake was dramatically reduced in the presence of the Na+/H+ exchange blocker and micropinocytosis inhibitor amiloride, suggesting that PepB2 invokes macropinocytosis. Moreover, we found that PepB2 had more efficient cell-penetrating activity than several other well-known CPPs (TAT, penetratin, Pep-1, and TP10). Finally, Tf assay-based screening of peptides derived from two other large clostridial toxins, TcdA and TcsL, uncovered two new TcdA-derived CPPs. In conclusion, we have identified six CPPs from large clostridial toxins and have demonstrated the ability of PepB2 to promote cell association and entry of several molecules through a putative fluid-phase macropinocytotic mechanism.
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PMID:Cell-penetrating peptides derived from Clostridium difficile TcdB2 and a related large clostridial toxin. 2924 10