The direct coupling of the carboxylic derivative of steroids to the amino group of enzymes is a well-established method in steroid enzyme immunoassays for making enzyme conjugates (1). Horseradish peroxidase (HRP), containing six lysine residues in the sequence, is a widely used enzyme in enzyme immunoassays; in practice, however , only one or two of these are generally available for reaction (...

A method for the rapid modification under mild conditions of carboxyl groups in proteins has been developed. The method involves the activation of the carboxyl group by a water-soluble carbodiimide and the subsequent reaction of the activated carboxyl group with a nucleophile such as glycine methyl ester. The kinetics of the reaction indicates that there are limits to the variation of carbodiim...

Irreversible inhibition of Na,K-ATPase and K+-dependent p-nitrophenylphosphatase activities was produced by incubation of purified Na,K-ATPase enzyme with 1-ethyl-3(3-dimethylaminopropyl)carbodiimide (EPC). Inhibition was time and [EPC] dependent and displayed first order kinetics with respect to time. The [EPC] to reduce the enzyme velocity by 50% for Na,K-ATPase and phosphatase activities was...

Three-step synthesis of 6-amino-2,3-dihydro-4-pyridinones from homoallylamines involving NBS-mediated cyclization of N-(3-butenyl)ureas to 6-(bromomethyl)-2-iminourethanes, dehydrohalogenation and a novel rearrangement as a key step has been developed. The scope and limitations of the method, as well as the mechanism of the rearrangement, supported by kinetic studies and the isolation of N-(1-a...

Crosslinking and the resultant changes in mechanical properties have been shown to influence cellular activity within collagen biomaterials. With this in mind, we sought to determine the effects of crosslinking on both the compressive modulus of collagen-glycosaminoglycan scaffolds and the activity of osteoblasts seeded within them. Dehydrothermal, 1-ethyl-3-3-dimethyl aminopropyl carbodiimide ...

The role of the interaction between actin and the secondary actin binding site of myosin (segment 565-579 of rabbit skeletal muscle myosin, referred to as loop 3 in this work) has been studied with proteolytically generated smooth and skeletal muscle myosin subfragment 1 and recombinant Dictyostelium discoideum myosin II motor domain constructs. Carbodiimide-induced cross-linking between filame...

Since the development of the Edmonton protocol, islet transplantation is increasingly encouraging as a treatment for type 1 diabetes. Strategies to ameliorate problems with the intraportal site include macroencapsulating the islets in diverse biomaterials. Characterization of these biomaterials is important to optimally tune the properties to support islets and promote vascularization. In this ...

OBJECTIVES Published transmission electron microscopy analysis of in vitro resin-dentin bonds shows that, after 44 months, almost 70% of collagen fibrils from the hybrid layer disappear. Matrix metalloproteinases (MMPs) play an important role in that process and are thought to be the main factor responsible for the solubilization of dentin collagen. Therefore, this study aimed to evaluate the i...