摘要:

ABSTRACTA homogenous endo‐polygalacturonase (EC3.2.1.15,) has been isolated from mature pickling cucumbers. This is the first report of an endo‐polygalacturonase in cucumbers. The enzyme was purified by three chromatography steps on Sephadex cation exchangers. The molecular weight is35,000daltons. With polygalacturonic acid as the substrate at an ionic strength (μ) of0.15,the pH optimum is5.6.The enzyme is not active atμ= 0.027.Maximum activity occurred atμ= 0.2.The half‐life of the enzyme is1.2min at70°Cin pH5.2, 0.1M acetate buffer. An inhibitor, isolated from the sericea lespedeza, which inhibits polygalacturonases from fungal sources, also inhibits the cucumber enzyme. This enzyme may be involved in tissue breakdown during the latter stages of fruit de

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1980.tb00873.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTAn alkaline protease was partially purified from the skeletal muscle of Atlantic croaker. The protease is a cytoplasmic enzyme and heat stable. The enzyme preparation was shown to degrade fish actomyosin in vitro between 50–60°C. The enzyme is a sulfhydryl protease and does not require Ca++ions for its activity. Preparations of the enzyme do not hydrolyze TAME, BTEE or denatured hemoglobin. Column chromatographic analyses suggest an apparent molecular weight of 80,000 ± 4,000 and the isoelectric point is 6.0 ±

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1980.tb00874.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTCrude preparations of peach fruit(Prunus persicaBatsch cv. Redskin) polyphenol oxidase (PPO) showed many apparent isoenzyme forms. Some of these forms were probably the result of proteolytic action of peach proteases while other forms were the result of association of PPO with carbohydrate materials.In the presence of protease inhibitors, Trasylol and phenylmethylsul‐fonyl fluoride, three apparent isoenzyme forms of PPO were purified to homogeneity. The purification scheme included hydrophobic chromatography on phenyl sepharose CL‐4B, hydroxylapatite chromatography, DEAE cellulose chromatography, and gel filtration on Ultrogel AcA 34. Minor contaminants remaining after these steps were separated from PPO by gel electrophoresis.The major PPO isoenzyme form (A) was purified 44 fold with an overall yield of 5.6% and contained no detectable carbohydrates. Isoenzyme forms A' and A' were purified104and67fold respectively, but still were associated with carbohydrate material. Cesium chloride centrifugation partially removed the carbohydrates associated with PPO A' and A'.Purified peach PPO A showed greater activity toward D‐catechin (539%) and pyrogallol(l82%) than to catechol (100%). An apparent K3of 4, 0.3, and 2 mM was obtained with D‐catechin, pyrogallol and catechol, respectively. The enzyme was severely inhibited by 10 μM 2,3‐naphthalenediol (91%) and by 10 pM diethyl dithiocarbam

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1980.tb00875.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTThe major soluble glycoprotein of potato tubers was isolated by chromatography on DEAE cellulose and Con A Sepharose. It contained about 5% neutral sugar and1%hexosamine, exhibited a molecular weight of45,000by SDS gel electrophoresis, and consisted of6–10ionic forms as revealed by isoelectric focusing. This glycoprotein comprised about20%of the soluble protein in all of the31tested potato cultivar

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1980.tb00876.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTCytidine 5′‐diphospho‐1,2‐diacyl‐sn‐glycerol (CDP‐diacylglycerol) is an important liponucleotide intermediate in the biosynthesis of phosphatidyl‐inositol, phosphatidylserine and phosphatidylglycerophosphate. The Agranoff‐Suomi method (Agranoff, B. W. and Suomi, W. D. (1963) Biochem. Prep. 10, 47–51) for the synthesis of CDP‐diacylglycerol was modified by a procedure which eliminates the lyophilization step required for the preparation of reactants. The reaction was run in chloroform instead of pyridine using the catalyst 4‐dimethylaminopyridine. The product of the reaction was purified by silica gel column chromatography and is enzymatically active with the enzymes phosphatidylinositol synthase, phosphatidylserine synthase and phosphatidylgl

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1980.tb00877.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY