Enzymatic modifications developing areas

AH cephalosporins found in nature (Tables 1 and 2) have the D-a-aminoadipic acid 7-acyl side chain (21). AH of these compounds can be classified as having rather low specific activity. A substantial amount of the early work in the cephalosporin area was unsuccessfiiHy directed toward replacing the aminoadipic acid side chain or modifying it appropriately by fermentation or enzymatic processes (6,22). A milestone ia the development of cephalosporins occurred in 1960 with the discovery of a practical chemical process to remove the side chain to afford 7-ACA (1) (1). Several related processes were subsequendy developed (22,23). The ready avaHabHity of 7-ACA opened the way to thousands of new semisynthetic cephalosporins. The cephalosporin stmcture offers more opportunities for chemical modification than does that of penicillins There are two side chains that especiaHy lend themselves to chemical manipulation the 7-acylamino and 3-acetoxymethyl substituents. 

The processes of prepropolypeptide synthesis, translocation, proteolytic processing and non-proteolytic modification can be enzymatically defined. These definitions are continuing to be developed and clarified. There are limited reports on insect neuropeptide processing (101.102. but these investigations should increase rapidly with the identification of precursor sequences via molecular genetics. The identification of processing enzymes, both proteolytic and non-proteolytic, will further open whole new areas for exploration. 

A novel procedure was developed to improve psyllium functionality by conducting a solid-state enzyme reaction. The procedure requires no special equipment/operation (such as freeze dry) and could be carried out without using any additional chemicals. To evaluate the solid-state enzymatic procedure, modified psyllium preparations were produced under selected reaction conditions, and analyzed for their water-absorbing capacity, gelling capacity, particle surface structure, and soluble and insoluble fiber contents. The results showed that structural modification improved psyllium functionality. Modified psyllium preparations had reduced water-absorbing capacity and less gelling ability. The reduced water-absorbing capacity may be explained by the decreased surface area of psyllium particles. In addition, the solid-state enzymatic treatments had much less effects on soluble fiber contents than the liquid phase enzymatic reactions. 

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