Coupling with Bovine Serum Albumin

Stereochemical probes for measuring wild-type or altered TK activity from en2yme variants with improved or new properties. The assay was validated using wild-type TK and probe 1 in the presence of D-R5P as the acceptor substrate. 

In this way, compound 1 is a substrate for TK, yielding a-hydroxyl and P-coumarinyl substituted aldehyde. The slow release of fluorescence compared with the results obtained with transaldolase from an appropriate fluorogenic probe is 

This biosensor was based on the immobilization of PPO within layered double hydroxides (LDHs), which are known to be efficient immobilization matrices for this enzyme [26]. LDHs are synthetic solids with positively charged bracite-like layers of mixed metal hydroxides separated by interlayered hydrated anions. 

The starting material was the protected L-tyrosine 9 with its carboxyhc acid function protected as an ethyl ester and its amine function protected by an acetyl group. After allylation of 9 followed by ozonolysis of the double bond of 12, 

Development of an Amperometric TK Assay The coupled TK reaction with probe 

---

The thioglycosides of the amide derivatives (4) and (5) have been coupled with bovine serum albumin using sodium cyanide and borane as coupling agents at pH 6-7 and 37 °C. ... 

FIA of anionics without a phase separation may be based on the quenching effect of surfactants on the fluorescence intensity of 8-anilino-l-naphthalenesulfonic acid coupled with bovine serum albumin (83). Another method of avoiding a phase separation is to use a surfactant-selective electrode. Since interference is a problem, the surfactant-selective electrode approach is best coupled with online concentration with a reversed-phase column. Such a system has been demonstrated for trace analysis of sodium dodecylsulfate (84). 

A radioimmunoassay method was developed that allows the measurement of picomole amounts of the alkaloid salsolidine (68) (237) it is useful in localizing the alkaloid in tissues and in cells. The agent was prepared by coupling 68 with bovine serum albumin by reductive N-alkylation. 

Fig. 9.10. Matrix eflFects in immunoassay are generally revealed as a decrease in absolute signal at any level of spiked anal5d e concentration. This effect decreases with the dilution of the sample. Example presented an indirect competitive ELISA for 4-nitrophenol in milk at different dilutions. A 4-nitrophenol derivative coupled to bovine serum albumin was used as the competitor, an anti-4-nitrophenol (polyclonal, from rabbit) as the antibody and goat anti-rabbit immunoglobulin G coupled to peroxidase as the detection system [43]. (Reprinted with permission.)...

Glycoproteins. — Pseudoglycoproteins have been synthesized by treating proteins with carbohydrates (see e.g.. Tables 1-5), chiefly for use in affinity chromatography. Oligosaccharides coupled to bovine serum albumin for use as immunogens include chito-oligosaccharides (also coupled to cytochrome c), lactose covalently attached to S-ethoxycarbonyloctanol, 4-isothiocyanato-... 

Electrochemistry can be coupled with other physical methods such as fluorescence spectroscopy. An XO-based electrochemiluminescent biosensor for hypoxanthine has been reported. The enzyme was immobilized in a carbon paste electrode with bovine serum albumin cross-linked with glutar-aldehyde. The working principle of the biosensor is illustrated in Scheme 5.6. As already shown (eqn (5.3a)), H2O2 is produced by the catalytic reaction between hypoxanthine and XO immobilized on the electrode surface. In an alkaline or neutral solution, luminol is electrochemically oxidized to a compound that reacts spontaneously with H2O2 to generate chemiluminescent luminol and the ensuing luminescence was used to quantify the amount of hypoxanthine present. 

A synthesis of A-acetylneuraminic acid (NeuNAc) relies upon a hetero-Diels-Alder reaction involving the mannose-derived unit (35) (mannose carbons numbered) as outlined in Scheme 11. 3 NeuNAc has been isolated by an improved procedure from the nests of the Chinese swiftlet, and coupled via aldehydes (36) with bovine serum albumin and tetanus toxoid. 4... 

The intermediate aldehydes produced from the slalosyl units of a glycoprotein by periodate treatment have been reductlvely aminated with glycine and cyanoborohydride. The resultant glycine-modified sialic acids were isolated by mild acid hydrolysis and characterised.49 Reductive amination has also been used to bond KDO and NeuNAc to 1,6-hexanediamine the saccharide-l-(6-aminohexyl)amines obtained were converted to isothiocyanates and coupled to bovine serum albumin for immunological studies. ... 

The catalytic hydrolysis of each molecule of these compounds releases two protons, the measurement and correlation of which to the OP concentration forms the basis of a potentiometric enzyme electrode. The basic element of this very simple enzyme potentiometric electrode is a pH electrode modified with an immobilized purified organophosphorus hydrolase (OPH) layer formed by cross-linking OPH with bovine serum albumin and glutaraldehyde. Thus, potentiometric OP biosensors were prepared by coupling OPH and a glass pH electrode. The sensors were constructed by immobilizing OPH on the surface of a pH-sensitive... 

---