Not available / text

published_or_final_version / abstract / toc / Electrical and Electronic Engineering / Master / Master of Philosophy

Chickpea (Cicer arietinum L.) seed is a potential source of protein ingredients with desirable nutritional and functional properties. Knowledge of molecular characteristics of a food protein is essential before a protein can gain widespread use as a food ingredient. The objectives of this study were to prepare chickpea proteins using different extraction methods and precipitation methods and to investigate molecular characteristics using polyacrylamide gel electrophoresis (PAGE; Native and SDS), reversed phase high performance liquid chromatography (RP-HPLC) and electrospray ionization mass spectrometry (ESI-MS) techniques. Proteins of ground chickpea seed were extracted with sodium hydroxide (NaOH) and with citric acid solutions and precipitated with addition of acid and by cryoprecipitation. The protein contents of the protein preparation ranged from 49% to 97%. The microstructures of chickpea protein isolates examined by scanning electron microscope (SEM) revealed the presence of starch grains in the cryoprecipitates from citric acid extraction but not in isoelectric precipitates. The globulins (legumins and vicilins), glutelins, and albumins from both citric acid and NaOH isolates were characterized by Native-PAGE. The cryoprecipitates contained mainly the globulin-rich proteins. With SDS-PAGE characterization, protein subunits were identified as follows: (i) legumin subunits: MW 40, 39, 26, 23, and 22 kDa, (ii) vicilin subunits: MW 50, 37, 33, 19, and 15 kDa, (iii) glutelin subunits: 58, 55, and 54 kDa, and (iv) albumin subunits: 10 kDa. Separation of fractions of isolated chickpea proteins by RP-HPLC showed that early eluting fractions (Rt 20-30 min) consisted of subunits of MW 6.5-31 kDa (SDS-PAGE). At elution time 30-36 min, the fractions obtained were composed mainly of mixtures of legumin and vicilin subunits (MW 14-45 kDa). The major subunits of chickpea protein fractions from both cryoprecipitates and isoelectric precipitates are legumin basic subunit (MW∼23 kDa) and vicilin-rich proteins (MW∼19, 17, 15 kDa). ESI-MS analysis of fractions separated by RP-HPLC showed MW ranging between 5.1 and 53.5 kDa. The subunits of MW 35366, 27626, 22864, 20531, 16092, and 15626 Da of fractions from ESI-MS corresponded to MW 35.3, 28.0, 24.1, 20.5, 16.1, and 15.3 kDa identified in SDS-PAGE. These fractions were identified as legumin-rich and vicilin-rich proteins.

HOX proteins are evolutionarily conserved homeodomain-containing transcription factors involved in hematopoiesis and patterning during embryogenesis. Their tasks as master regulators of embryonic development are achieved in large part through their ability to interact with co-factors of the PBX and MEIS/PREP families, which constitute the broader three amino-acid loop extension (TALE) class of homeodomain proteins. HOX, MEIS, and PBX have been implicated in leukemic hematopoiesis due to their association with hematological malignancies. The oncogenic function of MEIS1 in accelerating the onset of acute myeloid leukemia induced by HOX was mapped to its C-terminal transactivation domain, which is responsive to PKA signaling. This thesis extends our understanding regarding the mechanism by which MEIS1A executes its C-terminal transactivation function in vivo. We describe the involvement of CREB and its co-activators CBP and TORC in conferring the PKA-responsiveness of the ME1S1A C terminus. CREB mutants that fail to bind CBP or TORC also fail to promote PKA induction mediated by the C terminus of ME1S1A. TORC was further shown to be capable of bypassing the need for PKA to activate transcription by MEIS1, an ability endowed by its physical interaction with MEIS1. Chromatin immunoprecipitation (ChIP) demonstrated a concerted recruitment of endogenous MEIS1, TORC2, and CREB proteins on ME1S1 target genes. In addition, this thesis also characterizes the promoter of the murine Meis1 gene. Meis1 possesses multiple transcription start sites upstream of its translation initiation site. We identified a ME1S·PBX consensus recognition site within the Meis1 promoter and showed that PBX1 binds to this sequence in vitro. Our ChIP assay results further suggest an autoregulatory mode for the Meis1 gene as revealed by a co-occupancy of endogenous CREB, TORC2, PBX1, and MEIS1 itself on the Meis1 promoter. Collectively, this thesis proposes a mechanistic action conferred by CREB, CBP and TORC in the PKA-inducible transactivation of ME1S1A, and provides new information on the Meis1 promoter.

No description available.

Centrifugation of coconut milk resulted in cream, skim milk, and insoluble solids. Proteins were isolated from skim milk by the addition of acid, with or without heating. The separation and isolation gave the following coconut protein preparations: coconut milk, coconut skim milk, insoluble solids, acid precipitate, and acid-heat precipitate. / Trypsin inhibitory activity (TIA) of the coconut protein preparations was relatively low while tryptic digestibility of the isolated proteins was considerably lower than those of the coconut milk and skim milk, the digestibility of coconut protein preparations was lower than that of casein. In general, the emulsifying and farming properties of coconut protein preparations were lower than casein. The insoluble solids showed the highest viscosity when compared with the coconut protein preparations. In contrast to the whey protein concentrate (WPC), the apparent strain of gels from the acid precipitate increased as the pH increased. The gelation properties at pH 3 of the insoluble solids were better than WPC. / The estimated molecular weight by size-exclusion chromatography of coconut protein preparations gave 3 fractions with MW ranging from 6850 Da to 229402 Da. In native PAGE, coconut proteins were separated into at least 3 subunits and under SDS-denatured conditions, the major protein subunits showed MW of 54531 Da and 25008 Da, respectively. RP-HPLC separation of coconut milk, acid precipitate, and acid-heat precipitate gave 3 fractions containing several species of MW ranging between 35574 Da to 51209 Da when analyzed by mass spectometry.

Two leaves of amendments in pocket on front end paper. / Bibliography: leaves 177-185. / xix, 194 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Describes selective and nonselective procedures to extract recombinant protein from the cytoplasm of Escherichia coli. / Thesis (Ph.D.)--University of Adelaide, Dept. of Chemical Engineering, 1997

Diss. (sammanfattning) Uppsala : Univ., 2004. / Härtill 3 uppsatser.

Thesis (PhD) - Swinburne University of Technology, Industrial Research Institute Swinburne - 2006. / A thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy, Industrial Research Institute Swinburne, Swinburne University of Technology - 2006. Typescript. Includes bibliographical references (p. 184-197).

Thesis (Ph. D.)--University of Washington, 2008. / Vita. Includes bibliographical references (leaves 150-160).