Creatinine levels in biological fluids are important indicators for the clinical evaluation of renal function. Creatinase (CRE, EC3.5.3.3) is one of the key enzymes in the enzymatic measurement of creatinine concentration, and it is also the rate-limiting enzyme in the whole enzymatic cascade system. The poor catalytic activity of CRE severely limits its clinical and industrial applications. To address this issue, a semi-rational design is applied to increase the activity of a creatinase from Alcaligenes sp. KS-85 (Al-CRE). By high-throughput screen of saturation mutagenesis libraries on the selected hotspot mutations, multiple variant enzymes with increased activity are obtained. The five-point best variant enzyme (I304L/F395V/K351V/Y63S/Q88A) were further obtained by recombine the improved mutations sites that to showed a 2.18-fold increased specific activity. Additionally, structure analysis is conducted to understand the mechanism of the activity change. This study paves the way for a better practical application of creatinase and may help further understand its catalytic mechanism.
Creatinine ; Mutagenesis, Site-Directed ; Ureohydrolases/genetics* ; Catalysis

Renal cell carcinoma (RCC) is one of the most malignant tumors in urology, and due to its insidious onset patients frequently have advanced disease at the time of clinical presentation. Thus, early detection is crucial in management of RCC. To identify tumor specific proteins of RCC, we employed proteomic analysis. We prepared proteins from conventional RCC and the corresponding normal kidney tissues from seven patients with conventional RCC. The expression of proteins was determined by silver stain after two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). The overall protein expression patterns in the RCC and the normal kidney tissues were quite similar except some areas. Of 66 differentially expressed protein spots (p<0.05 by Student t-test), 8 different proteins from 11 spots were identified by MALDI-TOF-MS. The expression of the following proteins was repressed (p<0.05); aminoacylase-1, enoyl-CoA hydratase, aldehyde reductase, tropomyosin alpha-4 chain, agmatinase and ketohexokinase. Two proteins, vimentin and alpha-1 antitrypsin precursor, were dominantly expressed in RCC (p<0.05).
Aged ; Aldehyde Reductase/analysis ; Amidohydrolases/analysis ; Carcinoma, Renal Cell/*metabolism/pathology ; Comparative Study ; Electrophoresis, Gel, Two-Dimensional ; Enoyl-CoA Hydratase/analysis ; Female ; Fructokinases/analysis ; Humans ; Kidney Neoplasms/*metabolism/pathology ; Male ; Middle Aged ; Proteome/*analysis ; Proteomics/*methods ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Tropomyosin/analysis ; Ureohydrolases/analysis ; Vimentin/analysis ; alpha 1-Antitrypsin/analysis

OBJECTIVETo screen the differentially expressed proteins especially at the precancerous stage of diethylnitrosamine (DEN) induced hepatocarcinogenesis by comparative proteome research.

METHODSRats were divided into normal and DEN groups and sacrificed periodically. The liver samples were stained with gamma-glutamyl transpeptidase (GGT) and HE to distinguish the preneoplastic lesion (pre-HCC) from the normal and HCC tissues. The two-dimensional electrophoresis (2-DE) and mass spectrometry (MALDI-TOF-MS/MS) were then applied to analyze the differentially expressed protein between pre-HCC and normal tissues, pre-HCC and HCC, as well as HCC and normal tissues. A few of the candidate proteins such as laminin receptor 1 (67LR) and agmatinase were validated by Western blot and RT-PCR.

RESULTSTotally, there were 82 proteins that differentially expressed two fold or more in one kind of tissues sample than the other, 47 of which occurred in the pre-HCC tissues. Eight proteins including 67LR were consistently up-regulated from normal tissue to pre-HCC and then to HCC tissues, while 22 proteins including agmatinase showed progressively down-regulated in these tissues samples.

CONCLUSIONThe protein expression profiles are different during the process of hepatocarcinogenesis. Further study on the differentially expressed protein, especially these upregulated in the precancerous stage such as 67LR and agmatinase, might contribute to prevention and early diagnosis of human HCC.

Animals ; Blotting, Western ; Carcinoma, Hepatocellular ; chemically induced ; metabolism ; pathology ; Diethylnitrosamine ; Liver ; metabolism ; pathology ; Liver Neoplasms, Experimental ; chemically induced ; metabolism ; pathology ; Male ; Neoplasm Proteins ; metabolism ; Precancerous Conditions ; metabolism ; pathology ; Proteins ; metabolism ; Proteome ; Rats ; Rats, Wistar ; Receptors, Laminin ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Ureohydrolases ; metabolism ; gamma-Glutamyltransferase

Argininemia is a rare, autosomal recessive, metabolic disorder caused by an hereditary deficiency of hepatocytes arginase due to ARG1 gene defect. Arginase is the final enzyme in the urea cycle, catalyzing the hydrolysis of arginine to ornithine and urea. Research advances in the clinical manifestations, diagnosis, treatment, prenatal diagnosis and genetics of argininemia were reviewed in this paper. The clinical manifestations of patients with argininemia are complicated and nonspecific so that clinical diagnosis is usually difficult and delayed. Progressive spastic tetraplegia, seizures and cerebella atrophy are common clinical features of the disease. Blood amino acids analysis, arginase assay and ARG1 gene analysis are important to the diagnosis of argininemia. Early diagnosis and a protein-restricted diet with citrulline and benzoate supplements can contribute a lot to improve patient prognosis. With the application of liquid chromatography-tandem mass spectrometry in selective screening and newborn screening for inborn errors of metabolism, an ever-increasing number of patients with argininemia are detected at the asymptomatic or early stages.
Arginase ; genetics ; Humans ; Hyperargininemia ; diagnosis ; genetics ; therapy ; Molecular Biology ; Prognosis

OBJECTIVE: To explore the genetic basis for an infant with early-onset argininemia. METHODS: Potential variant was detected with an Ion Torrent semiconductor sequencer using a gene panel for inherited diseases. Suspected variants were verified by Sanger sequencing. RESULTS: Genetic testing indicated that he has carried c.560+2T>C and c.811T>C compound heterozygous variant of the AGR1 gene, which were inherited from his father and mother, respectively. Among these, c.560+2T>C was suspected to be pathogenic, while c.811T>C was of unknown clinical significance, and both were not reported previously. CONCLUSION The c.560+2T>C and c.811T>C compound heterozygous variants of the AGR1 gene probably underlies the argininemia in this child. Above finding has enriched the variant spectrum of the AGR1 gene.
Arginase ; genetics ; Female ; Genetic Testing ; Humans ; Hyperargininemia ; genetics ; Infant ; Male

OBJECTIVETo explore the effect of storage time on arginase level, and the possible source of arginase in suspended red blood cells (RBC).

METHODSThe arginase and myeloperoxidase (MPO) levels in suspended RBC and control plasma were detected by ELISA. The free hemoglobin level in suspended RBC and control plasma were detected by colorimetric method. The relationship between arginase level, MPO level and free hemoglobin level in suspended RBC was analyzed by the related methods.

RESULTSThe arginase and free hemoglobin levels in suspended RBC were higher than those in control plasma. Otherwise, MPO level was not significantly different between suspended RBC and control plasma. All of them did not increase along with prolonging of storage time. There was not a significant correlation between arginase level and free hemoglobin level in suspended RBC of different storage time (r = 0.03), but arginase level positively correlated with MPO level in the suspended RBC of different storage time (r = 0.76).

CONCLUSIONThe arginase level in suspended RBC storaged for different time increases significantly, but not along with prolonging of storage time. The main possible source of arginase in the suspended RBC is the residual white blood cell, especially neutrophils.

Arginase ; chemistry ; Blood Preservation ; Erythrocytes ; enzymology ; Humans ; Peroxidase ; chemistry ; Plasma ; enzymology ; Time Factors

The effect of taxol on the production of nitric oxide(NO) and reactive oxygen radicals(O2- and H2O2)and on the function of phagocytic activity of murine microglial cells were investigated. Stimulated cells also showed increased production such reactive oxygen radicals as surperoxide and hydrogen peroxide measured by luminometer after stimulated with phorbolmyristate acetate(PMA). Taxol alone had only being small effect on NO synthesis, whereas taxol in combination with rIFN-gamma synergistically increased NO synthesis in a dose dependent manner. The production of NO by taxol plus rIFN-gamma was reduced by such L-arginine analogues as N(G)-mono-metyl-L-arginine Monohydrate(N(G)MMA), and N-amino-L-arginine(NAA) and arginase which decomposes L-arginine. Collectively, the data illustrate the potential for taxol to activate microglia-mediated anticancer mechanisms in the brain in addition to its better characterized effects on ovarian, beast, and lung cancer.
Arginase ; Arginine ; Brain ; Hydrogen Peroxide ; Lung Neoplasms ; Oxygen ; Paclitaxel* ; Reactive Oxygen Species

To better understand the role of macrophages in early stages of experimental autoimmune myocarditis (EAM), we compared the expression of inducible nitric oxide synthase (iNOS) and arginase-1, markers for classically activated M1 and alternatively activated M2 macrophages, respectively, in the hearts of EAM-affected and control rats. Immunohistochemical evidence revealed that both iNOS-positive and arginase 1-positive macrophages were found in EAM lesions, while some cells were co-localized with both markers. This finding suggests that the increased level of arginase-1, which is partly from M2 macrophages, contributes to the modulation of EAM, possibly through the reduction of nitric oxide in the lesion.
Animals ; Arginase ; Heart ; Macrophages* ; Myocarditis* ; Nitric Oxide ; Nitric Oxide Synthase Type II ; Rats*

Arginine deprivation is a novel antimetabolite strategy for the treatment of arginine-dependent cancers that exploits differential expression and regulation of key urea cycle enzymes. Several studies have focused on inactivation of argininosuccinate synthetase 1 (ASS1) in a range of malignancies, including melanoma, hepatocellular carcinoma (HCC), mesothelial and urological cancers, sarcomas, and lymphomas. Epigenetic silencing has been identified as a key mechanism for loss of the tumor suppressor role of ASS1 leading to tumoral dependence on exogenous arginine. More recently, dysregulation of argininosuccinate lyase has been documented in a subset of arginine auxotrophic glioblastoma multiforme, HCC and in fumarate hydratase-mutant renal cancers. Clinical trials of several arginine depletors are ongoing, including pegylated arginine deiminase (ADI-PEG20, Polaris Group) and bioengineered forms of human arginase. ADI-PEG20 is furthest along the path of clinical development from combinatorial phase 1 to phase 3 trials and is described in more detail. The challenge will be to identify tumors sensitive to drugs such as ADI-PEG20 and integrate these agents into multimodality drug regimens using imaging and tissue/fluid-based biomarkers as predictors of response. Lastly, resistance pathways to arginine deprivation require further study to optimize arginine-targeted therapies in the oncology clinic.
Arginase ; Arginine ; Argininosuccinate Lyase ; Argininosuccinate Synthase ; Biomarkers ; Carcinoma, Hepatocellular ; Drug Combinations ; Epigenomics ; Glioblastoma ; Humans ; Kidney Neoplasms ; Lymphoma ; Melanoma ; Sarcoma ; Urea ; Urologic Neoplasms

In this study, the effect of phorbol ester on the synthesis of nitric oxide(NO) in murine microglial cells was examined. Phorbol 12-myristate 13-acetate(PMA), a protein kinase C(PKC) activator, alone had no effect, whereas PMA with recombinant interferon-gamma(rIFN-gamma) synergistically increased NO synthesis in murine microglial cells. The maximal effect of PMA in the increase of NO synthesis always fit with the range for rull activation of PKC in these cells. The increase of NO synthesis was reflected as increased amount of inducible NO synthase(iNOS) mRNA by Northern blotting. Treatment of PKC inhibitors such as staurosporine(STSN) or polymxin B decreased rIFN-gamma plus PMA-stimulated NO synthesis. Further, prolonged incubation of the cells with PMA, which down regulate PKC activity, abolished synergistic cooperative effect with IFN-gamma. N(G)-monomethyl-L arginine monohydrate(NGMMA), an analogue of L-arginine, and arginase inhibited rIFN-gamma plus PMA-induced NO production in murine microglial cells. On the basis of these observations we conclude that PKC might not be involved in the expression of iNOS, but instead, might be involved in the post-transcriptional modification of iNOS mRNA.
Arginase ; Arginine ; Astrocytes ; Blotting, Northern ; Microglia ; Myristic Acid* ; Nitric Oxide Synthase Type II ; Nitric Oxide* ; Protein Kinase C ; Protein Kinases ; RNA, Messenger