Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

p21v-H-ras, the transforming protein of Harvey murine sarcoma virus, contains a covalently attached lipid. Using thin-layer chromatography, we identified the acyl group as the 16-carbon saturated fatty acid palmitic acid. No myristic acid was detected in fatty acids released from in vivo-labeled p21v-H-ras. The p21v-K-ras protein encoded by Kirsten sarcoma virus was also palmitylated. The processing and acylation of p21v-K-ras however differed from that of p21v-H-ras. Three forms of [3H]palmitic acid-labeled p21ras proteins were detected in Kirsten sarcoma virus-transformed cells. This contrasted with Harvey sarcoma virus, in which two forms of p21v-H-ras contained palmitic acid. Analysis by partial proteolysis of p21v-H-ras labeled with [3H]palmitic acid suggested that all of the lipid found in intact p21v-H-ras was located in the C-terminal region. On sodium dodecyl sulfate-polyacrylamide gels, p21v-H-ras labeled with [3H]palmitic acid migrated slightly ahead of the majority of p21v-H-ras. Of the mature forms of p21v-H-ras, apparently only a subpopulation contains palmitic acid.
Mol Cell Biol 1986 Jan
PMID:Direct identification of palmitic acid as the lipid attached to p21ras. 302 17

Many bioactive peptides terminate with an amino acid alpha-amide at their COOH terminus. The enzyme responsible for this essential posttranslational modification is known as peptidyl-glycine alpha-amidating monooxygenase or PAM. We identified cDNAs encoding the enzyme by using antibodies to screen a bovine intermediate pituitary lambda gt11 expression library. Antibodies to a beta-galactosidase/PAM fusion protein removed PAM activity from bovine pituitary homogenates. The 108,207 dalton protein predicted by the complete cDNA is approximately twice the size of purified PAM. An NH2-terminal signal sequence and short propeptide precede the NH2 terminus of purified PAM. The sequences of several PAM cyanogen bromide peptides were localized in the NH2-terminal half of the predicted protein. The cDNA encodes an additional 430 amino acid intragranular domain followed by a putative membrane spanning domain and a hydrophilic cytoplasmic domain. The forms of PAM purified from bovine neurointermediate pituitary may be generated by endoproteolytic cleavage at a subset of the 10 pairs of basic amino acids in the precursor. High levels of PAM mRNA were found in bovine pituitary and cerebral cortex. In corticotropic tumor cells, levels of PAM mRNA and pro-ACTH/endorphin mRNA were regulated in parallel by glucocorticoids and CRF.
Mol Endocrinol 1987 Nov
PMID:Structure of the precursor to an enzyme mediating COOH-terminal amidation in peptide biosynthesis. 315 62

Coenzyme A (CoA) degradation was studied in isolated working hearts from acutely diabetic rats (48 h). Hearts from diabetic rats had elevated levels of total CoA (752 +/- 15 nmol/g dry) compared to control (537 +/- 14 nmol/g dry). When hearts from diabetic animals were perfused for 5 mins with perfusate containing pyruvate, (5 mM) and glucose (11 mM) CoA levels remained unchanged. Addition of palmitate, (1.2 mM) and glucose (11 mM) to the perfusate, however, resulted in a rapid drop in CoA levels to 672 +/- 19 nmol/g dry. Palmitate had no effect on CoA levels in control hearts which did not have elevated levels of CoA. Addition of insulin to the buffer containing glucose and palmitate prevented the decrease in CoA levels in diabetic hearts. The level of long chain acyl CoA in diabetic hearts perfused with pyruvate was 105 +/- 11 nmol/g dry, and did not change when insulin was present in the perfusate. In the presence of palmitate, levels of long chain acyl CoA increased from 76 +/- 16 to 149 +/- 13 nmol/g dry, and, in this case, addition of insulin caused a further increase to 192 +/- 18 nmol/g dry. Thus, the lower rate of CoA degradation in the presence of insulin was associated with a rise in long chain acyl CoA levels. In a separate series of experiments, CoA levels were increased in control hearts in vitro (from 537 +/- 14 to 842 +/- 19 nmol/g dry). Subsequent perfusion of these hearts that contained elevated CoA with palmitate also resulted in a rapid drop of CoA to 655 +/- 17 nmol/g dry.(ABSTRACT TRUNCATED AT 250 WORDS)
J Mol Cell Cardiol 1987 Mar
PMID:Coenzyme A degradation in the heart: effects of diabetes and insulin. 329 61

We directly expressed human R-ras 23,000-dalton protein (p23) cDNA in Escherichia coli under the control of the trp promoter. GTP-dependent phosphorylation of a p23 threonine 85 substitution mutant was observed. This result is in direct analogy to the autokinase activity of H-ras and K-ras threonine 59 substitution mutants. Normal p23 protein was detected in the human fibrosarcoma cell line HT1080 by immunoprecipitation with rabbit antibodies raised against an E. coli-expressed R-ras fusion protein. The R-ras p23 protein was found to be 3H labeled in the presence of [9,10(n)-3H]palmitic acid and is associated with the P100 membrane fraction of HT1080 cells. These data suggest that human R-ras p23 has biochemical properties very similar to those of the p21 products of the H-, K-, and N-ras proto-oncogenes. We constructed an R-ras minigene and engineered the expression of normal and mutant alleles from the simian virus 40 early region promoter. Normal and mutant R-ras gene products were authenticated by transient expression in COS-7 cells and immunoprecipitation. The valine 38-substituted R-ras p23 displayed reduced electrophoretic mobility. R-ras p21-like proteins, made by eliminating the first 26 R-ras codons, displayed evident mobility differences between the pro form and mature form, along with a valine 12 substitution-dependent change in electrophoretic mobility. Rat-1 fibroblasts were transfected with normal and mutant R-ras alleles and normal and activated H-ras alleles. Unlike the human T24 bladder oncogene-encoded p21, mutant R-ras alleles do not cause monolayer focus formation or growth in soft agar of rat fibroblasts.
Mol Cell Biol 1987 Aug
PMID:Heterologous expression and characterization of the human R-ras gene product. 331 5

The fatty acid composition of phospholipids and triglycerides in heart muscle was examined in normal and alloxan-diabetic male Wistar rats. In diabetes the major phospholipids, phosphatidyl choline and phosphatidyl ethanolamine, showed significant changes in fatty acid composition, whereas cardiolipin and phosphatidyl serine + phosphatidyl inositol did not show marked changes in fatty acid profile. In phosphatidyl choline there was a significant diminution in arachidonic acid, 20 : 4(n-6) and palmitic acid, 16 : 0, and a corresponding increase in linoleic acid, 18 : 2(n-6), and stearic acid, 18 : 0. In phosphatidyl ethanolamine the level of 20 : 4(n-6) was significantly reduced. The diabetic heart had normal levels of individual phospholipids, whereas the triglycerides were increased by 90% and contained significantly higher levels of 18 : 2(n-6). The results confirm that diabetes is associated with a diminution in fatty acid desaturation, affecting the fatty acid composition of phosphatidyl choline in particular. These changes may be relevant to development of atherosclerosis and relative resistance to catecholamine-induced cardiac necrosis in diabetes.
J Mol Cell Cardiol 1987 Nov
PMID:Reduced arachidonic acid levels in major phospholipids of heart muscle in the diabetic rat. 343 62

Dictyostelium discoideum synthesizes a 23,000 Mr protein, p23dd-ras, closely related to the mammalian oncogene-encoded protein p21ras. To investigate the subcellular localization of p23dd-ras, conditions were optimized to reduce protein degradation following cell breakage. Subcellular fractionation of D. discoideum showed that p23dd-ras was associated predominantly with the membrane fraction during both vegetative growth and differentiation. In the absence of suitable protease inhibitors considerable amounts of a truncated form of p23dd-ras were recovered in the cytosol fraction, suggesting that intact p23dd-ras is attached to the membrane by a short terminal peptide sequence. Radio-isotope labelling of D. discoideum with myristic acid or palmitic acid in the presence of excess unlabelled acetate resulted in radio-isotope incorporation into a select group of proteins including p23dd-ras. No acyl label appeared in the truncated cytoplasmic form of p23dd-ras when cell breakage was performed in the absence of suitable protease inhibitors, indicating that the acyl group is associated with the short terminal peptide that is cleaved. These data suggest that p23dd-ras, like its mammalian counterpart, is acylated and associated with the plasma membrane. There was no evidence during a 30-minute pulse of methionine for a cytoplasmic precursor to the membrane-bound p23dd-ras, suggesting that the turnover of the presumptive precursor must be much more rapid in D. discoideum than for pro-p21ras in mammalian cells.
Mol Microbiol 1987 Nov
PMID:A ras-encoded protein in Dictyostelium discoideum is acylated and membrane-associated. 344 63

Synchronised gametocyte cultures were used to study the biosynthesis of the sexual stage target antigens (Mr 230 000, 48 000 and 25 000) for anti gamete/zygote antibodies. These antigens were shown to be synthesized during gametocyte development from day 2-3 onwards until gametogenesis occurred. After gametogenesis a 25 kDa protein was predominantly synthesized, whereas synthesis of the other target proteins was hardly detectable. The 48, 45, and 25 kDa proteins appeared to be glycosylated, in addition the 25 kDa was also acylated in that it bound [3H]palmitic acid covalently. The iso-electric point (pI) of these proteins was assessed as being 6.0 +/- 0.1 (for both 48 and 45 kDa) and 5.6 +/- 0.1 (for 25 kDa).
Mol Biochem Parasitol 1986 Aug
PMID:Characterization of Plasmodium falciparum sexual stage antigens and their biosynthesis in synchronised gametocyte cultures. 352 48

The internal consistency of the PAM matrix model of protein evolution is here investigated. The 1 PAM matrix has been constructed from amino acid replacements observed in closely related sequences. Such replacements are of two types, those that do not require an intermediate amino acid replacement and those that do. The second type of replacement must generally be produced by a repetition of the first. This allows data on the first type to be used in predicting data on the second type so that some elements of the 1 PAM matrix may be used to predict others. A discrepancy of more than two orders of magnitude is found between the predictions and the data when this is carried out. This is partly accounted for by an error in constructing the matrix. However, it also seems necessary that the basic model be modified. Several possibilities are considered. One of these is to incorporate a site-dependent spectrum of mutabilities associated with each amino acid.
Mol Biol Evol 1985 Sep
PMID:On the PAM matrix model of protein evolution. 387 Aug 70

Acetate, propionate, ethanol and propanol were the predominant end-products released during incubation of a thiabendazole resistant and a susceptible strain of Trichostrongylus colubriformis. The parasites in all the incubations appeared to be deficient in reducing equivalents if the end-products arose from the classical catabolic pathway through fumarate reductase (EC 1.3.1.6). Possible alternative pathways for accounting for redox balance, including beta-oxidation, the pentose phosphate pathway and amino acid metabolism were investigated. Palmitate was oxidised aerobically. Radiolabelled tricarboxylic acid cycle intermediates, citrate and alpha-ketoglutarate, were decarboxylated to 14CO2 indicating that at least a partial tricarboxylic acid cycle to succinyl-CoA via alpha-ketoglutarate operates both anaerobically and aerobically in T. colubriformis. These data and the pattern of end-products suggest the presence of two pathways to propanol and propionate either through fumarate reduction or alpha-ketoglutarate oxidation. T. colubriformis may apportion carbon flow through these pathways to maintain a stable redox ratio. Similar calculations on previously reported data indicate that both pathways may also operate in Haemonchus contortus. Exposure of resistant T. colubriformis to thiabendazole under anaerobic conditions caused an increased accumulation of end-products, especially propanol, in the incubation medium. The alpha-ketoglutarate pathway may lower the dependence of the parasite on the fumarate reductase route which is sensitive to thiabendazole. The operation of the alpha-ketoglutarate pathway, with propanol as an end-product, may provide a mechanism for regulating redox balance in trichostrongylidae.
Mol Biochem Parasitol 1985 Mar
PMID:The contribution of a partial tricarboxylic acid cycle to volatile end-products in thiabendazole-resistant and susceptible Trichostrongylus colubriformis. 399 Jul 6

We have studied the synthesis and expression of surface proteins in zygotes of Plasmodium gallinaceum during their transformation to mature ookinetes. The cells were biosynthetically labelled in vitro using [35S]methionine and proteins were immunoprecipitated with rabbit anti-ookinete serum or monoclonal antibodies. Early zygotes (approx. 2 h post-gametogenesis and fertilization) synthesized and expressed on their surface a protein of Mr 26 000 as observed under reducing conditions on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE) (31 000 under non-reducing conditions) and continued to do so for 8-10 h; thereafter synthesis of the Mr 26 000 protein declined and little or none was synthesized in the mature ookinetes (greater than 20 h post-gametogenesis). Between 3-5 h post-gametogenesis, zygotes also began to synthesize a protein of Mr 28 000 (34 000 under non-reducing conditions). Synthesis and expression of this surface protein continued throughout development; and the Mr 28 000 protein was the predominant surface protein synthesized by the mature ookinete. Mr 26 000 and Mr 28 000 proteins have been designated earlier as PgO-1 and PgO-2 respectively (Carter and Kaushal, Mol. Biochem. Parasitol. (1984) 13, 235-241). Neither protein was synthesized in the gametocytes prior to gametogenesis. Both proteins could be labelled with [3H]glucosamine or [3H]mannose. When zygotes were incubated with [3H]palmitic acid both PgO-1 and PgO-2 bound fatty acids in covalent linkage. The two proteins do not otherwise appear to be structurally related. They were differentially immunoprecipitated by different monoclonal antibodies and gave rise to distinct patterns of peptides following digestion with proteases such as Staphylococcus aureus V-8, trypsin and chymotrypsin.
Mol Biochem Parasitol 1985 Feb
PMID:Biosynthesis of two stage-specific membrane proteins during transformation of Plasmodium gallinaceum zygotes into ookinetes. 403 6


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>