A low molecular weight acid phosphatase was purified to homogeneity from chicken heart with a specific activity of 42 U/mg and a recovery of about 1%. Nearly 800 fold purification was achieved. The molecular weight was estimated to be 18 kDa by SDS-polyacrylamide gel electrophoresis. Para-nitrophenyl phosphate, phenyl phosphate and flavin mononucleotide were efficiently hydrolysed by the enzyme and found to be good substrates. Fluoride and tartrate had no inhibitory effect while phosphate, vanadate and molybdate strongly inhibited the enzyme. The acid phosphatase was stimulated in the presence of glycerol, ethylene glycol, methanol, ethanol and acetone, which reflected the phosphotransferase activity. When phosphate acceptors such as ethylene glycol concentrations were increased, the ratio of phosphate transfer to hydrolysis was also increased, demonstrating the presence of a transphosphorylation reaction where an acceptor can compete with water in the rate limiting step involving hydrolysis of a covalent phospho enzyme intermediate. Partition experiments carried out with two substrates, para-nitrophenyl phosphate and phenyl phosphate, revealed a constant product ratio of 1.7 for phosphotransfer to ethylene glycol versus hydrolysis, strongly supporting the existence of common covalent phospho enzyme intermediate. A constant ratio of K (cat)/K (m), 4.3 x 10(4), found at different ethylene glycol concentrations, also supported the idea that the rate limiting step was the hydrolysis of the phospho enzyme intermediate.

Acid phosphatases (EC 3.1.3.2) are widely distributed in nature and often occur in multiple forms differing in molecular sizes, localization within the cell, substrate specificity and sensitivity to inhibitors. 1) In animals its biological role is not yet clear but it is involved in many biological systems which are linked to energy metabolism, metabolic regulation and cellular signal transduction path ways. 2)Mammalian liver contains two acid phosphatase forms (molecular weight 90-107 kDa and 14-30 kDa) and these can be separated by gel chromatography on Sephadex G-75. [3][4][5][6] The effects of inhibitors, substrates and kinetic parameters also distinguish between the enzymes. 7-9) The acid phosphatase (molecular weight 107 kDa) purified from human liver to homogeneity had been extensively characterized. 5,8) The enzymes from liver of carp, catfish and frog had also been purified [10][11][12] and found to be glycoprotein in nature. Previously, low molecular weight acid phosphatases had been purified from human liver, 9,13) bovine liver, 3,14,15) rat liver, 16,17) porcine liver, 18) bovine heart, 19,20) brain, 21) human placenta 22) and human erythrocytes. 23) In all cases, the enzymes had molecular weights ranging between 14-18 kDa.Two distinct isoforms of low molecular weight acid phosphatase exist in rat liver (AcP1 and AcP2), human erythrocytes (B fast and B slow ) and human placenta (HCPTP-A and HCPTP-B) and these have also been isolated, characterized and sequenced. 17,24,25) The AcP1, B fast and HCPTP-A have been classified as IF-1 while AcP2, B slow , HCPTP-B, bovine heart PTPase and bovine liver PTPase as IF-2. IF-1 and IF-2 differ from each other in type specific sequence of the 40-73 regions, in substrate affinity and in the sensitivity to activators and inhibitors. 26) In our laboratory we have also purified and characterized these enzyme couples from chicken liver 27) and uromastix liver. 28) These differ in pyridoxal-5Ј-PO 4 inhibition, cGMP activation and some kinetic parameters. Both isoenzyme couples possess phosphotyrosine protein phosphatase activity. None of all enzymes (LM-ACP and HM-ACP) need metal ion for their activity.Another class of acid phosphatases called Zn ϩϩ -dependent acid phosphatases, exist in two forms of different molecular weight. 29,30) Zn ϩϩ -dependent acid phosphatases have also been isolated and characterized in the liver of different vertebrates. 31)This paper describes the purification and characterization of LM-ACP and HM-ACP from fish (Labeo rohita) liver and the resolution of the two low molecular weight isoenzymes (IF-1 and IF-2 types) by affinity chromatography on paminobenzyl phosphonic acid-agarose column. MATERIALS AND METHODSMaterials L. rohita (common name Rohu) was captured from Indus river (N.W.F.P. Pakistan) and liver was excised immediately and stored at 4°C for use. para-Nitrophenyl phosphate (pNPP), phenyl phosphate, flavin mononucleotide (FMN), phosphotyrosine and other substrates were purchased from Merk, Fluka and Sigma Chemical Co.; SDS molecular ...

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Plants have been used since ancient times as an important source of biologically active substances. Specific activities of these plant extracts are generally linked to the presence of secondary metabolites together with their phenolic contents. Present study aimed at investigating the total phenolic and flavonoid contents, and antioxidant activity of selected plants from five different families. The total phenolic content was measured using Folin-Ciocalteu assay and total flavonoid content by aluminum chloride colorimetric method. The antioxidant capacity was estimated by phosphomolybdinium assay. Our findings indicates that total phenolic content for methanolic extracts ranged from 27.07 to 59.11 mg GAE/g DW, and total flavonoid content ranged from 38.37 to 124.23 mg QE/g DW, with an antioxidant activity ranging from 55.82 to 129.06 mg AAE/g DE. Following trend was shown in the assessment of total phenolic and flavonoid contents: Rhazya stricta>Cicer arietinum>Solanum melongena>Solanum surattense>Solanum nigrum>Withania sominifera>Sisymbrium irio>Withania coagulans>Raphanus sativus>Fagonia indica>Brassica napus. While the antioxidant capacity followed the trend: Cicer arietinum>Solanum nigrum>Withania coagulans>Rhazya stricta>Raphanus sativus>Solanum melongena>Withania sominifera>Solanum surratense>Fagonia indica>Brassica napus>Sisymbrium irio. It is also seen that both wild and cultivated plants have higher medicinal value, which can be linked to the phenolic and flavonoid content, and antioxidant potential. Findings of the study revealed that wild plants possess higher phenolic content compared to cultivated plants, whereas cultivated plants had higher antioxidant activity.

Wheat is recognized as one of the most important dietary elements due to its high nutritious content and thus, has become greatest food option all over the world. Phosphorus (P) being major plant food nutrient plays a vital role multiple functions of plant growth and development. The current study was carried out to compare the performance of phosphate solubilizing bacteria (PSB) as bio-fertilizer with commercially available phosphate fertilizers on wheat crop. The trial was designed in randomized complete block (RCB) replicated thrice. 6 different sources of phosphate fertilizers (Di-ammonium phosphate as DAP, Nitrophos as NP, Single super phosphate as SSP, Restore as PSB, Marathon as PSB, Nitrogen (N2) fixing bacteria as PSB) followed by control were evaluated for agronomic, physiological and quality attributes of wheat. The results showed that most of the qualitative traits were significantly influenced by different treatments. However, application of N2 fixing bacteria was more significant in all treatments. Highest total viable count of colony-forming units (14.63×106 at 3-WAS & 17.70×106 after harvest CFU g-1), maximum tillers’ count (337 m-2), grains’ count (45.57 spike-1), grain yield (2714.3 kg ha-1), LAI (0.67 & 1.16 at 56 & 112 DAS), CGR (13.59 g day-1 m-2), photosynthesis rate (26.13 µ mol m-2 sec-1) and flag leaf sugar content (0.24%) were recorded on account of using N2-fixing bacteria applied as PSB. Moreover, NPK content in shoot, grain as well as uptake of NPK by grain were also received as highest in the same treatment. Based on research findings, it is concluded that application of N2-fixing bacteria as PSB (7.5 kg ha-1) might be increasing wheat production in Dera Ismail Khan and other areas of similar environment in Pakistan.