Indole 3-acetic acid (IAA) was analyzed in apple, orange, and prune tissue by GC-MS by monitoring the protonated molecular ion of its methyl ester at mass to charge ratio (m/z) 190 together with the major fragment ion at m/z 130 and the corresponding ions from the methyl esters of either [(2)H(4)]IAA (m/z 194, 134) or [(2)H(5)]IAA (m/z 195, 135). Abscisic acid (ABA) was analyzed by monitoring t...

Subtilisin BPN' hydrolysed N-acetyl-l-3-(2-naphthyl)-alanine methyl ester, N-acetyl-l-leucine methyl ester and N-acetyl-l-valine methyl ester, faster than alpha-chymotrypsin. Of eight ;locked' substrates tested, only methyl 5,6-benzindan-2-carboxylate was hydrolysed faster by subtilisin, whereas the other esters were better substrates for chymotrypsin. Compared with the values for chymotrypsin,...

A tissue kallikrein has been isolated from rat heart extracts by DEAE-Sepharose and aprotinin-affinity column chromatography. The purified cardiac enzyme has both N-tosyl-L-arginine methyl ester esterolytic and kinin-releasing activities, and displays parallelism with standard curves in a kallikrein radioimmunoassay, indicating it to have immunological identity with tissue kallikrein. The enzym...

The ability of trypsinogen to catalyze its own activation was studied at pH 8.1 in the presence of Ca++ ions. The lag phase portion of the classical S-shaped curve of activation was shortened by increasing the trypsinogen concentration but was extended by pretreatment of the zymogen with diisopropyl fluorophosphate or soybean trypsin inhibitor. Despite these pretreatments, however, full activat...

This study examined the concentration (mg/g) of trans polyunsaturated fatty acid (TPFA) in five soybean oil brands by gas-liquid chromatography. Tricosanoic acid methyl ester was used as the internal standard. All samples analyzed presented trans 18:2 fatty and trans 18:3 acids in detectable amounts. The concentration of TPFA ranged from 5.8 to 30.2 mg/g, with a mean concentration value of 18.4...

reaction of aryl methyl ketone with isatin in the presence of a base afforded 2- arylquinoline-4-carboxylic acid (3). reaction of diazomethane with compound 3 yielded the ester 4. compound 5 was prepared from the reaction of n, n'-dialkylethyl (or propyl) arnine with 4. addition of hydrazine hydrate to compound 4a gave 2- (2- pyridyl) quinoline-4-carboxylic acid hydrazide (6). reaction of ...

A novel automated transesterification (ATE) technique has been developed for the quantitative determination of acid components used in synthesizing ester-based oils. The ATE technique has been successfully tested over a period of more than five years using several commercially available ester-based new and used refrigeration oils and jet oils. In this automated technique, the ester-based oil is...

Since the isolation and identification of the sesquiterpene antibiotic pentalenolactone (1),1-7) several other related metabolites have been recognized in strains of Streptomyces, notably pentalenolactones E (2),8,9) G (3),10) and H (4),11) pentalenic acid (5),11,12) and the parent hydrocarbon, pentalenene (6).11-15)* Besides their novel structural features, these compounds are all potential in...

An interesting observation was found during our continued studies on the hydrolysis of ibuprofen esters by Candida rugosa lipase (CRL). An important role is played by pH in the stereospecific hydrolysis of these esters. The flap region of CRL plays a significant role in the access of the substrate to the active site of the enzyme. At pH 5.6, 48% of the methyl ester and 5% of the butyl ester of ...

Polyoxometalate-bis-pyrene receptors for phenyl-C61-butyric acid methyl ester (PCBM) provide an interfacial layer (IFL) material enhancing the open circuit voltage of organic photovoltaic device about 34% under applied bias ±5 V.