Novel AGLP-1 albumin fusion protein as a long-lasting agent for type 2 diabetes.

Glucagon like peptide-1 (GLP-1) regulates glucose mediated-insulin secretion, nutrient accumulation, and ß-cell growth. Despite the potential therapeutic usage for type 2 diabetes (T2D), GLP-1 has a short half-life in vivo (t(1/2) <2 min). In an attempt to prolong half-life, GLP-1 fusion proteins were genetically engineered: GLP-1 human serum albumin fusion (GLP-1/HSA), AGLP-1/HSA which has an additional alanine at the N-terminus of GLP-1, and AGLP-1-L/HSA, in which a peptide linker is inserted between AGLP-1 and HSA. Recombinant fusion proteins secreted from the Chinese Hamster Ovary-K1 (CHO-K1) cell line were purified with high purity (>96%). AGLP-1 fusion protein was resistant against the dipeptidyl peptidase-IV (DPP-IV). The fusion proteins activated cAMP-mediated signaling in rat insulinoma INS-1 cells. Furthermore, a C57BL/6N mice pharmacodynamics study exhibited that AGLP-1-L/HSA effectively reduced blood glucose level compared to AGLP-1/HSA.

Expression and characterization of a novel deoxyribose 5-phosphate aldolase from Paenibacillus sp. EA001.

A novel deoC gene was identified from Paenibacillus sp. EA001 isolated from soil. The gene had an open reading frame (ORF) of 663 base pairs encoding 220 amino acids with a molecular mass of 24.5 kDa. The amino acid sequence was 79 % identical to that of deoxyribose 5-phosphate aldolase (DERA) from Geobacillus sp. Y412MC10. The deoC gene encoding DERA was cloned into expression vector and the protein was expressed in Escherichia coli. The recombinant DERA was purified by using Ni-NTA affinity chromatography and characterized. The optimum temperature and pH for DERA were 50 degrees C and 6.0, respectively. The specific activity for deoxyribose 5-phosphate (DR5P), substrate, was 62 micronmol/min/mg. The Km value for DR5P was determined to be 145 mM with the Kcat value of 3.2 times 10(2 /sec) from Lineweaver-Burk plots. The EA001 DERA showed stability toward a high concentration of acetaldehyde (100 mM).

Purification and characterization of a novel glucansucrase from Leuconostoc lactis EG001.

A gene encoding glucansucrase was identified in Leuconostoc lactis EG001 isolated from lactic acid bacteria (LAB) in Kimchi, a traditional Korean fermented food. The L. lactis EG001 glucansucrase gene consists of 4503 bp open reading frame (ORF) and encodes an enzyme of 1500 amino acids with an apparent molecular mass of 165 kDa. The deduced amino-acid sequence showed the highest amino-acid sequence identity (75%) to that of dextransucrase of L. mesenteroides. The gene was cloned and over-expressed in Escherichia coli strain. The recombinant enzyme was purified via Ni-NTA affinity chromatography and its enzymatic properties were characterized. The enzyme exhibited optimum activity at 30 degrees C and pH 5.0. In addition, the enzyme was able to catalyze the glycosylation of l-ascorbic acid to l-ascorbic acid 2-glucoside. The glycosylated product via EG001 glucansucrase has the potential as an antioxidant in industrial applications.

Comparative proteomic analysis of mouse melanoma cell line B16, a metastatic descendant B16F10, and B16 overexpressing the metastasis-associated tyrosine phosphatase PRL-3.

Metastasis is a complex, multistep process by which a cancer cell leaves the primary tumor, travels to a distant site via the circulatory system, and establishes a secondary cancer. A deeper understanding of the molecular events underlying metastasis will provide information that will be useful for the development of new diagnostic and therapeutic strategies. The B16 and B16F10 mouse melanoma cell lines are widely used as model system for studying many aspects of cancer biology including metastasis. Compared with B16, which has a low metastatic potential, the highly metastatic cell line B16F10 displayed a higher metastatic ability along with higher expression levels of the metastasis-associated phosphatase of regenerating liver-3 (PRL-3). B16 cells transfected with PRL-3 cDNA (B16-PRL3) had metastatic abilities comparable to those of Bl16F10 cells. To study the molecular mechanisms that underlie metastasis, the proteomes of the B16, B16F10, and B16-PRL3 cell lines were compared using two-dimensional differential in-gel electrophoresis. Proteins that varied significantly in levels between these cell lines were selected and identified using mass spectrometry. Interestingly, many proteins, especially those present in membrane fractions, were similarly up- or downregulated in both the Bl16F10 and B16-PRL3 cells lines compared to B16 cell lines. The list of similarly regulated proteins included heat shock protein 70, fascin-1, septin-6, ATP synthase beta subunit, and bone morphogenic protein receptor type IB. These proteins may play a causal role in PRL-3-mediated metastasis. These investigations open an avenue for the further characterization of the molecular mechanisms that underlie metastasis.

Cloning, expression, and characterization of a new deoxyribose 5-phosphate aldolase from Yersinia sp. EA015.

A new deoC gene encoding deoxyribose 5-phosphate aldolase (DERA) was identified in Yersinia sp. EA015 isolated from soil. The DERA gene had an open reading frame (ORF) of 672 base pairs encoding 223 amino acids to yield a protein of molecular mass 24.8 kDa. The amino acid sequence was 94% identical to that of DERA from Yersinia intermedia ATCC 29909. DERA was over-expressed in Escherichia coli and purified using Ni-NTA affinity chromatography. The specific activity was 137 micromol/min/mg. The Michaelis constant (k(m) value) of DERA was 9.1 mM. DERA was optimally active at pH 6.0 and 50 degrees C. DERA was tolerant to a high concentration (300 mM) of acetaldehyde.

Identification of proteins binding to decursinol by chemical proteomics.

Decursinol, found in the roots of Angelica gigas Nakai, has been traditionally used to treat anemia and other various diseases. Recently, numerous biological activities such as cytotoxic effect on leukemia cells, and antitumor, neuroprotection, and antibacterial activities have been reported for this compound. Although a number of proteins including protein kinase C, androgen receptor, and acetylcholinesterase were proposed as molecular targets responsible for the activities of decursinol, they are not enough to explain such a diverse biological activity mentioned above. In this study, we employed a chemical proteomic approach, leading to identification of seven proteins as potential proteins interacting with decursinol. Most of the proteins contain a defined ATP or nucleic acid binding domain and have been implied to be involved in the pathogenesis and progression of various human diseases including cancer, autoimmune disorders, or neurodegenerative diseases. The present results may provide clues to understand the molecular mechanism of the biological activities shown by decursinol, an anticancer natural product.

Potent inhibition of recombinant human cytochrome p-450 1A1 by pentamethoxystilbene.

Previously it was reported that various hydroxystilbene compounds strongly inhibit human cytochrome P-450 1 enzymes and were postulated as candidate chemopreventive agents. In this study, the inhibitory potential of P-450 1 enzyme activities by 3,5,3,4,5-pentamethoxystilbene (PMS), a synthetic stilbene compound, was evaluated with the Escherichia coli (E. coil) membranes of recombinant human cytochrome P-450 1A1, 1A2, or 1B1 coexpressed with human NADPH-P-450 reductase. PMS produced a significant inhibition of ethoxyresorufin O-deethylation (EROD) activities with IC50 values of 0.14, 934, and 3.2 M for 1A1, 1A2, and 1B1, respectively. PMS did not significantly inhibit EROD activities in human liver microsomes. To elucidate the mechanism of inhibition by PMS, kinetic studies were performed. Analysis of the mode of inhibition indicated a mixed-type inhibition of P-450 1A1. The inhibition of P-450 1A1-mediated EROD activity by PMS was not irreversible-mechanism based. The loss of EROD activity of P-450 1A1 with PMS was blocked by trapping agents such as glutathione, N-acetylcysteine, or dithiothreitol. Moreover, PMS significantly suppressed P-450 1A1-mediated EROD activity and P-450 1A1 gene expression in HepG2 cells induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Taken together, the results suggested that PMS is a potent and selective inhibitor of human P-450 1A1 and may be considered for use as a cancer chemopreventive agent in humans.

Potent inhibition of human cytochrome P450 1 enzymes by dimethoxyphenylvinyl thiophene.

Cytochrome P450 (P450) 1 enzymes such as P450 1A1, 1A2, and 1B1 are known to be involved in the oxidative metabolism of various procarcinogens and are regarded as important target enzymes for cancer chemoprevention. Previously, several hydroxystilbene compounds were reported to inhibit P450 1 enzymes and were rated as candidate chemopreventive agents. In this study, we investigated the inhibitory effect of 2-[2-(3,5-dimethoxyphenyl)vinyl]-thiophene (DMPVT), produced from the chemical modification of oxyresveratrol, on the activities of P450 1 enzymes. The inhibitory potential by DMPVT on the P450 1 enzyme activity was evaluated with the Escherichia coli membranes of the recombinant human cytochrome P450 1A1, 1A2, or 1B1 coexpressed with human NADPH-P450 reductase. DMPVT significantly inhibited ethoxyresorufin O-deethylation (EROD) activities with IC50 values of 61, 11, and 2 nM for 1A1, 1A2, and 1B1, respectively. The EROD activity in DMBA-treated rat lung microsomes was also significantly inhibited by DMPVT in a dose-dependent manner. The modes of inhibition by DMPVT were non-competitive for all three P450 enzymes. The inhibition of P450 1B1-mediated EROD activity by DMPVT did not show the irreversible mechanism-based effect. The loss of EROD activity in P450 1B1 with DMPVT incubation was not blocked by treatment with the trapping agents such as glutathione, N-acetylcysteine, or dithiothreitol. Taken together, the results suggested DMPVT to be a strong noncompetitive inhibitor of human P450 1 enzymes that should be considered as a good candidate for a cancer chemopreventive agent in humans.