Conjugate hydrolysis

Almost all the specific chemical reactions in biodegradation can be classified as oxidation-reduction, hydrolysis, or conjugation. Hydrolysis and oxidation-reduction have been discussed before. Conjugation involves the addition of functional groups or a hydrocarbon moiety to an organic... 

Sulfation and sulfate conjugate hydrolysis, catalyzed by various members of the sul-fotransferases (SULT) and sulfatase enzyme superfamilies, play important roles in the... 

The other biological fluid commonly assayed is mine. Unlike plasma or serum this contains only low concentrations of protein so protein removal is not necessary. The composition of urine varies widely and so does the volume passed by different individuals. Generally speaking large volumes are available for analysis. One of the major problems with urine is the large number of small organic compounds that are present. Liquid-liquid extraction (often preceded by conjugate hydrolysis) is often the sample preparation procedure used for urine analysis. 

An acid-labile linker of c/ -aconityl or hydrazone between DOX and HPMA was synthesized to release the drug in the endosomes and lysosomes after endocy-totic uptake of the conjugate. Hydrolysis of the linkage occurs at weak acidic pH therefore, the release of DOX at plasma pH is insignificant. The in vivo activity of the acid-sensitive conjugate was significantly enhanced in comparison with free DOX and PKl. ... 

II) ruminants are more effective than mono-gastric animals at conjugate hydrolysis. 

Drug conjugates hydrolysis Chemical hydrolysis of drug metabolites Hydrolysis Commonly available equipment and reagents... 

Since polyphenols are retained until they, or their metabolic products, are excreted by the urine or faeces, they undergo a number of complex microbial and chemical transformations that may include chemical conjugation, hydrolysis and biliary excretion [12], The few existing studies in humans show that the quantities of polyphenols found intact in urine vary from one phenolic compound to another. Among flavonoids, recovery is low for some flavonols, such as quercetin and rutin (0.3-14%), but high for other flavonoids, such as catechins, anthocyanins, flavanones and soy isoflavones (3-27%) [13],... 

The gas-phase analytical techniques have been used for the analysis of urinary steroids for a long time. The determinations of urinary estrogens, progesterone metabolites, 17-ketosteroids and, to a lesser degree, corticosteroid metabolites, with packed-column GC are extensively documented in the earlier monographs on the subject [274,290]. Various sample treatments, approaches to conjugate hydrolysis, and volatile derivatives have been described. Among those steroids, aldosterone stands out as a uniquely difficult substance to derivatize and determine. 

Fig. 1. Diagram of the metabolic reactions that determine pool size of the free lAA in plant cells. Inputs include (A) de novo synthesis from non-tryptophan and tryptophan pathways (B) conjugate hydrolysis and (C) transport. Outputs from the lAA pool inelude (D) oxidative catabolism (E) conjugate synthesis (F) transport and (G) possible lAA use during growth and developmental processes.

Where there are several possible sources of hormone, e.g. de novo synthesis and conjugate hydrolysis, the rates of individual pathways may be compared with the overall turnover rate, giving a measure of the relative importance of the different routes. 

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