Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Synthetic chocolate colourant, flavourant and the mixture of both were administered to healthy adult male albino rats to evaluate their effect on the nucleic acids metabolism, i.e. deoxyribonucleic and ribonucleic acids (DNA and RNA), total serum protein, thyroid hormones (T4 and T3) and nuclease enzymes, i.e. cytoplasmic- and mitochondrial deoxyribonuclease and ribonuclease (DNase and RNase) in brain, liver, and kidneys. Also, the activity of the fundamental enzymes of the oxidative pentose phosphate pathway, i.e. cytoplasmic and mitochondrial glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase (G-6-PD and 6-PGD), as well as total lipids and cholesterol contents in the same organs were studied. Ingestion of the studied food additives significantly increased serum protein, RNA and T4 hormone, while, DNA and T3 hormone were insignificantly elevated. In connection with this, the hydrolytic enzymes of nucleic acids (DNase and RNase activities) were stimulated by all studied food additives and in all mentioned organs. The activity of G-6-PD and 6-PGD in both cytoplasmic and mitochondrial fractions of all studied organs were increased. The highest increase was noticed in rats fed on diets supplemented with the mixture of both colourant and flavourant followed by colourant then flavourant, respectively.
 ...
PMID:Biochemical effect of chocolate colouring and flavouring like substances on thyroid function and protein biosynthesis. 171 48

A fluorescent compound has been detected in proteins browned during Maillard reactions with glucose in vitro and shown to be identical to pentosidine, a pentose-derived fluorescent cross-link formed between arginine and lysine residues in collagen (Sell, D. R., and Monnier, V. M. (1989) J. Biol. Chem. 264, 21597-21602). Pentosidine was the major fluorophore formed during nonenzymatic browning of ribonuclease and lysozyme by glucose, but accounted for less than 1% of non-disulfide cross-links in protein dimers formed during the reaction. Pentosidine was formed in greatest yields in reactions of pentoses with lysine and arginine in model systems but was also formed from glucose, fructose, ascorbate, Amadori compounds, 3-deoxyglucosone, and other sugars. Pentosidine was not formed from peroxidized polyunsaturated fatty acids or malondialdehyde. Its formation from carbohydrates was inhibited under nitrogen or anaerobic conditions and by aminoguanidine, an inhibitor of advanced glycation and browning reactions. Pentosidine was detected in human lens proteins, where its concentration increased gradually with age, but it did not exceed trace concentrations (less than or equal to 5 mumol/mol lysine), even in the 80-year-old lens. Although its precise carbohydrate source in vivo is uncertain and it is present in only trace concentrations in tissue proteins, pentosidine appears to be a useful biomarker for assessing cumulative damage to proteins by nonenzymatic browning reactions with carbohydrates.
 ...
PMID:Formation of pentosidine during nonenzymatic browning of proteins by glucose. Identification of glucose and other carbohydrates as possible precursors of pentosidine in vivo. 190 67

Various chemical modifications were created in short-interfering RNAs (siRNAs) to determine the biochemical properties required for RNA interference (RNAi). Remarkably, modifications at the 2'-position of pentose sugars in siRNAs showed the 2'-OHs were not required for RNAi, indicating that RNAi machinery does not require the 2'-OH for recognition of siRNAs and catalytic ribonuclease activity of RNA-induced silencing complexes (RISCs) does not involve the 2'-OH of guide antisense RNA. In addition, 2' modifications predicted to stabilize siRNA increased the persistence of RNAi as compared with wild-type siRNAs. RNAi was also induced with chemical modifications that stabilized interactions between A-U base pairs, demonstrating that these types of modifications may enhance mRNA targeting efficiency in allele-specific RNAi. Modifications altering the structure of the A-form major groove of antisense siRNA-mRNA duplexes abolished RNAi, suggesting that the major groove of these duplexes was required for recognition by activated RISC*. Comparative analysis of the stability and RNAi activities of chemically modified single-stranded antisense RNA and duplex siRNA suggested that some catalytic mechanism(s) other than siRNA stability were linked to RNAi efficiency. Modified or mismatched ribonucleotides incorporated at internal positions in the 5' or 3' half of the siRNA duplex, as defined by the antisense strand, indicated that the integrity of the 5' and not the 3' half of the siRNA structure was important for RNAi, highlighting the asymmetric nature of siRNA recognition for initiation of unwinding. Collectively, this study defines the mechanisms of RNAi in human cells and provides new rules for designing effective and stable siRNAs for RNAi-mediated gene-silencing applications.
 ...
PMID:siRNA function in RNAi: a chemical modification analysis. 1292 53

Lectins, a class of proteins that reversibly and non-enzymatically bind specific sugars, have been purified from different kinds of legumes. In this study, a 48-kDa lectin (KBL) was purified from Korean large black soybeans using liquid chromatography. The specific hemagglutinating activity of the KBL was 4096 titer/mg. EDTA-induced loss of hemagglutinating activity of KBL could be recovered by addition of Fe(3+) ions and some divalent cations as Ca(2+), Mn(2+), Fe(2+), Cu(2+), Zn(2+), and Pb(2+). Sugars such as D-(+)-galactose, D-(+)-raffinose, L-(+)-arabinose, alpha-D-(+)-melibiose, and alpha-lactose could inhibit the hemagglutinating activity of the lectin. Furthermore, the protein showed high thermal stability as well as stability over a wide range of pH values. KBL inhibited HIV-1 reverse transcriptase activity with an IC(50) of 1.38 microM. However, it was destitute of cytokine releasing, mitogenic, ribonuclease and antifungal activities. In addition, inhibitory activity toward nasopharyngeal cell lines was undetectable in KBL at concentrations up to 20 microM.
 ...
PMID:Biochemical and functional properties of a lectin purified from korean large black soybeans--a cultivar of glycine max. 1971 33