摘要:

A comprehensive review giving a bird's eye view of all the known tea enzymes is made. It is an observed fact that the enzymes play an important role in tea making. The enzymes are broadly categorized into four important groups. In light of recent work, methods of their isolation, their properties and their interactions with some of the commonly used chemicals in the tea industry, are discussed at length. Emphasis is placed on the specific role of each enzyme in relation to the quality of tea. The future lines and trends of research methodology have been evaluated in the light of previous work in the field.

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1984.tb00328.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Two α‐amylase inhibitors from black bean (Phaseolus vulgaris) were purified to homogencity using ammonium sulfate fractionation, DEAE‐Sephadex chromatography, phenyl‐Sepharose hydrophobic interaction chromatography and gel filtration with Sephadex G‐100. The inhibitors were designated I–1 and I–2 based on their order of elution from the phenyl‐Sepharose column. Both inhibitors are mannose containing glycoproteins, composed of subunits; active against porcine pancreatic, human salivary, and insect α‐amylases and inactive against bacterial, mold, and plant α‐amylases. The inhibitors I‐1 and I–2 have molecular weights of 49,000 and 47,000 and isoelectric points 4.93 and 4.86, respectively. Both inhibitors have similar amino acid compositions and are rich in aspartic acid, serine, glutamic acid, valine, and threonine and are low in sulfur containing amino acids. I–2 is more resistant to

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1984.tb00329.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

The effects of molecular organization on the interaction of peroxidizing lipids with proteins were studied by using human red cell membranes. Intact and chloroform‐disrupted membranes were oxidized. Disruption of membranes was achieved by treatment with chloroform and subsequent elimination of the solvent. Lipid oxidation rates and SDS‐electrophoretic protein patterns in the two types of membranes were compared. Specific3H‐DIDS label of band 3 allowed the study of the role of intrinsic proteins in the aggregation process. Lipid oxidation rate is not greatly affected by chloroform disruption although disrupted membranes show a higher rate of protein aggregation. α‐Tocopherol decreases lipid oxidation and protein aggregation rates. Band 3 protein dimers (188,000 M.W.) appear earlier than the higher molecular weight protein aggregates (400,000 M.W.). The results suggest that native membrane organization prevents protein damage upon lipid pero

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1984.tb00330.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Phosphatidylglycerophosphate synthase (CDP‐diacylglycerol:sn‐glycerol‐3‐phosphate phosphatidyltransferase, EC 2.7.8.5) activity was identified from the crude mitochondrial fraction of germinating soybeans. The mitochondrial enzyme exhibited pH optima at 7.0 and 9.5. Phosphatidylglycerophosphate was the predominate product at pH 9.5 while phosphatidylglycerol was the predominate product at pH 7.0. At pH 9.5, maximum phosphatidylglycerophosp‐hate synthase activity was dependent on manganese (0.5 mM), magnesium (10 mM), or cobalt (20 mM) ions and Triton X‐100 (0.5 mM). The apparent Kmvalues for CDP‐diacylglycerol and glycerol‐3‐phos‐phate were 0.1 mM and 0.17 mM, respectively. Activity was completely stable to temperatures up to 70°C and the energy of activation was 3.16 Kcallmole. Thioreactive agents slightl

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1984.tb00331.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Examination of the thermograms of cod muscle to which various salts have been added indicate that NaI decreases transition energies of both myosin and actin as compared to a no salt control, and to NaCl and Na2SO4treated samples. In contrast, CaCl2and MgCl2increases but broadens the peaks.

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1984.tb00332.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Book reviewed in this article:Chemistry&Biochemistry of Marine Food Products.Food Research and Data Analysis.Unconventional Sources of Dietary Fiber.Leaf Protein Concentrates.Developments in Sweeteners ©2.Handbook of Tropical Foods.Xenobiotics in Foods and Feeds.Basic Food Chemistry

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1984.tb00333.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY