Enzymic Hydrolysis Of Proteins Research Articles

Enzymic Hydrolysis of Protein During Barley Spent Grains Mashing

Enzymic Hydrolysis of Protein During Barley Spent Grains Mashing

Enzymic hydrolysis of protein during barley spent grains mashing

High nitrogen barley syrup (HNBS) was obtained by mashing barley spent grains with neutral proteinase. The total nitrogen to carbohydrate ratio in the HNBS was three times higher than in typical barley syrup. In order to enhance the liberation of free amino acids, the spent grains were hydrolysed simultaneously with proteinase and barley peptidase extract; the α-amino to total nitrogen ratio increased from 11.4 to 14.6%. During mashing with peptidase extract, the protein solubilization rate was lower than during mashing with neutral proteinase only. Data analysis by means of the modified Foster-Niemann equation suggested that endopeptidase inhibitors, possibly present in the peptidase extract, caused by decrease of protein solubilization rate. The isolation of the bacterial proteinase inhibitors from peptidase extract indicates that they affected the protein solubilization process.

Enteral Nutrition in the Early Postoperative Period: A New Semi‐Elemental Formula Versus Total Parenteral Nutrition

Several studies have reported that gastrointestinal (GI) intolerance symptoms are the limiting factor to enteral alimentation in the immediate postoperative period and often the reason for resorting to total parenteral nutrition (TPN). We postulated that Reabilan HN (a recently developed small peptide-based formula, in part obtained by enzyme hydrolysis of proteins) might be better absorbed and better tolerated so as to avoid the need for TPN. Accordingly, 19 patients undergoing major abdominal surgery were randomly assigned to receive Reabilan HN via jejunostomy or an equicaloric isonitrogenous TPN regimen. Both were begun 6 hr postoperatively at 25 ml/hr and increased by 25 ml/hr at 12-hr intervals up to the rate providing 1.5 times the calculated REE. GI tolerance to enteral feeding was excellent during the first three postoperative days, allowing the progression of the feeding rate to 99% of goal. During the next 3 days (starting on average 1.7 days after the return of bowel sounds), GI intolerance symptoms required a reduction in feeding rate to 52% on average. Subsequently, the symptoms resolved and the feeding rate reached 96% of goal. Although overall mean daily calorie and nitrogen intakes were lower for the enteral than for the TPN group (79.6 +/- 10.2% vs 94.6 +/- 3.8% of goal; p less than 0.01), the enteral group was nevertheless in positive caloric and nitrogen balance, and maintained similar serum albumin, prealbumin, and plasma transferrin levels. Average daily cost of supplies was $44.36 for enteral vs $102.10 for parenteral nutrition (p less than 0.001). We conclude that enteral feeding using this formula is well tolerated and cost-effective in the immediate postoperative period.(ABSTRACT TRUNCATED AT 250 WORDS)

The role of spindle pole bodies and modified microtubule ends in the initiation of microtubule assembly in Saccharomyces cerevisiae

The spindle poles of the budding yeast, Saccharomyces cerevisiae, have been removed from mitotic and meiotic cells by osmotic lysis of spheroplasts. The spindle pole bodies (SPBs)--diskoidal structures also termed 'spindle plaques'--have been analysed for their ability to potentiate the polymerization of microtubules in vitro. Free SPBs were completely deprived of any detectable native microtubules by incubation in the absence of added tubulin and were then challenged with chick neurotubulin, which had been rendered partially defective in self-initiation of repolymerization. Electron microscopy revealed that these SPBs served as foci for the initiation of microtubule polymerization in vitro. Because the attached microtubules elongated linearly with time but did not increase in numbers after the first stage of the reaction, it is apparent that there are a limited number of sites for initiation. The initiating potential of the SPBs was found to be inhibited by enzymic hydrolysis of protein but not of DNA. The microtubule end proximal to the site of initiation on the SPB is distinguished by a 'closed' appearance because of a terminal component which is continuous with the microtubule wall, whereas the distal end has the 'open' appearance characteristic of freely repolymerized neurotubules. SPBs which were partially purified on sucrose gradients retained their ability to initiate the assembly of microtubules with the same structural differentiation of their ends. The occurrence of closed proximal ends on native yeast microtubules suggests that closed ends may play a role in the initiation of microtubule polymerization in vivo, as well as in vitro.