Immobilized enzymes. I. Immobilization of carboxypeptidase CN, a preparation from Citrus natsudaidai Hayata

Direct monitoring of sequential enzymatic hydrolysis of peptides by thermospray mass spectrometry

A procedure for peptide sequencing using an immobilized exopeptidase column directly coupled to a thermospray mass spectrometer is described. The amino acids sequentially released from the C-terminus of the peptide chain are directly introduced into a thermospray ion source by a flowing aqueous buffer. The buffer is essential for the direct production of ions from solution. The method eliminates the need to derivatize the amino acids for detection and, by comparison to standard injections, amino acid sequence information can be obtained in less than two minutes. With the present configuration, detection limits are typically in the low picomolar range.

Modification of plant proteins by immobilized proteases

A potential application of plant proteins could be a replacement of animal proteins now in use in the food industry on the basis of certain specific functional properties plant proteins have. Modification of the chemical structure of selected plant proteins is needed to replace more expensive animal proteins as food ingredients that have specific functional characteristics. Structure modification may be achieved by physical, chemical, or microbiological methods, or by a combination of these. Immobilized enzyme techniques offer significant advantages for protein modification. Knowledge of the molecular properties of plant proteins is essential to understand the basis of protein functionality, to modify proteins so that they acquire desirable functional properties, and to predict potential applications of modified plant proteins. This paper reviews all the above mentioned aspects of plant protein chemistry and potential utilization.