Enzyme immobilization is the core technology of biocatalysis. Over the past few decades, enzyme immobilization research mainly focused on single enzyme immobilization. In recent years, multi-enzyme immobilization attracts more and more attention as it could increase the local concentration of reaction and improve the reaction yield. In this review, a summary of the recent progress, together with our research, is presented. Special emphasis is placed on four methods in multi-enzymes co-immobilization, namely, the nonspecific covalent co-immobilization, the nonspecific non-covalent co-immobilization, the non-covalent encapsulation co-immobilized and the site specificity co-immobilized. Finally, some industrial uses of immobilized multi-enzymes were addressed and the application prospect of multi-enzyme immobilization was highlighted.
Biocatalysis ; Enzymes, Immobilized

Peacekeeping is a military operation under certain conditions.In the special operations,the military personnel will have a special emotional response,mainly tension.It includes physical and psychological stress,based on the cognition and evaluation of the environment and forms of military activities.The psychological problems of peacekeepers caused by peacekeeping operation have been identified as one of the major reasons for non-combat attrition.Thus,researches on mental health of peacekeepers should not be ignored.So,we reviewed the interaction between peacekeeping operations and peacekeepers'mental health,and a few psychological intervention techniques to provide theoretical and practical basis for serving peacekeepers with mental health.

Aim To investigate the specific binding of folate conjugated PGA to FR-positive tumor cells.Method Folate-PGA and PGA were radiolabeled with 125I by the Iodogen method to examine the binding of PGA to FR positive HeLa cells and SKOV3 cells, or FR negative A549 cells. Results 125I-folate-PGA showed specific bound to HeLa cells and SKOV3 cells; Scatchard analysis of the data estimated the Kd of binding to be 0.11 nmol?L-1 and 0.25 nmol?L-1 respectively. 125I-folate-PGA showed virtually little specific binding to A549 cells which lack folate receptors. Conclusions folate-PGA displayed high affinity and good targeting activities for FR-positive tumor cells and the data warranted further studies for enzyme prodrug therapy.

Many factors influence the elastin-like polypeptides (ELPs) self-assembled into micron-sized particles. However, few efforts were made to investigate these factors. Using the ELPs [KV8F]n as the target, we studied systematically the factors with the dynamic light scattering. Our results show that the particle size increased and the uniform of particles decreased with the increase of the molecular weight. The analysis of size variation in self-assembled ELPs in response to changes in salt concentration indicated that the size increased with increasing the salt concentration, and the opposite response was observed when the concentration was above 0.4 mol/L. Under these conditions, the particles are micron-sized and larger than 1.1 μm. However, when the fusions containing the same ELPs and xylanase or 1,3-propanediol oxidoreductase, the size of the self-assembled ELPs particles decreased dramatically, which was only about 1/10 of that of the free ELPs. We proposed that the solvent accessible charged area of the enzymes could interact with the ELPs, the sterical hindrance of the enzymes prevent the aggregation of the ELPs. This might be the most important parameter in altering the particle size sharply.
Elastin ; chemistry ; Molecular Weight ; Particle Size ; Peptides ; chemistry ; Salts ; chemistry

Combination chemotherapy and nanoparticle drug delivery are two promising strategies in cancer treatment. The use of multiple therapeutic agents in combination provides synergistic effects among different drugs against cancer cells and suppresses drug resistance through distinct mechanisms of action.Nanocarriers can improve anti-tumor effects of drugs and reduce systemic toxicity through delivering drugs into the tumor tissue specially. Recently, many studies are aiming to encapsulate multiple agents into nanocarriers to optimize the anti-tumor effects. In the present review, the recent advances of nanoparticle platforms applied with co-delivering two or more drugs were summarized and the various combination strategies based on nanoparticles in oncology were discussed.

Dietary fiber contents in 34 common foods perchased in Beijing markets have been determined with detergent method, including neutral detergent fiber, acid detergent fiber, cellulose, hemicellulose and lignin. On dry basis, the dietary fiber contents of vegetables varied with kinds of food: the dietary fiber contents were higher in tender stems, leaves, stalks and flowers; lower in starchy tubers and roots; medium in non-starchy tubers and roots. The propotions of dietary fiber components were different in various categories of foods. Cellulose was the major component in vegetables and legumes, but in most cereals, hemicellulose content was higher than cellulose. All foods had the lowest lignin content with the exception of garlic bolt.

Objective To investigate the relationship between the anti-earthquake military rescuers' psychosomatic health and social support, and observe the effect of intervention to the army men who suffered troubles.Methods By cluster random sampling, 152 military rescuers and 139 army men not taking part in the rescues were investigated by Facility Psychosomatic Health Scale and Social Support Rating Scale. Mental intervention or medication was performed to those produced psychosomatic health. Results The scores of somatic symptoms,mental status,psychosomatic health and social support of military rescuers and the control group were (4.09±4.70) ,(2.18 ±3.16) ,(6.27 ±7.08) ,(6.14 ±4.20) and (2.11 ±4.16) ,(1.37 ±3.09),(3.47 ±6.55),(4.57 ± 4.17 )respectively, the difference was significant(P＜0.05). The somatic symptoms had significantly positive correlation with mental status in military rescuers (r=0.17～0.52, P＜ 0.05 or 0.01 ). Failure of social support had positive correlation with mental disorders (r=0.18～0.40, P＜0.05 or 0.01). The degree of social support was the main factor which had affected on the psychosomatic health of military rescuers. The somatic symptoms of military rescuers were apparently higher than their mental symptoms. Mental and pharmaceutical intervention showed good effect on them. Conclusion There is an apparent effect for military rescuers injured seriously psychosomatic health through medication or mental intervention.

In this work, we systematically analyzed the secondary structure amino acid compositions of acidic and alkaline enzymes and compared them with neutral ones. We found that the propensity of the individual residues to participate in secondary structures and the consistently higher composition of neutral and tiny residues might be the general stability mechanisms for their adaptation to pH extremes. Based on this, we presented a secondary structure amino acid composition method for extracting useful features from sequence. The overall prediction accuracy evaluated by the 10-fold cross-validation reached 80.3%. Comparing our method with other feature extraction methods, the improvement of the overall prediction accuracy ranged from 9.4% to 18.7%. The random forests algorithm also outperformed other machine learning techniques with an improvement ranging from 2.7% to 21.8%.
Algorithms ; Amino Acids ; chemistry ; Bacteria ; enzymology ; Enzymes ; chemistry ; classification ; Hydrogen-Ion Concentration ; Models, Chemical ; Protein Structure, Secondary

It is of theoretical and practical significance to understand the mechanism of enzyme adaptation to acidic and alkaline environments and classification of them based on sequence information. In present work, the amino acid composition of 105 acidic and 111 alkaline enzyme sequences was systematically analyzed. Acidic enzymes contained significantly more Trp, Tyr, Thr and Ser, whereas less Glu, Lys, Met and Arg. On the other hand, alkaline enzymes have slightly more Trp, Ala and Cys, whereas less Lys, Arg and Glu. The amount of Ala, Glu, Leu, Asn, Arg, Ser and Thr in acidic and alkaline enzymes varied largely. Hence, a weighted amino acid composition method was developed for the discrimination of acidic and alkaline enzymes. Using the back-check and the 5-fold cross validation methods, the overall accuracy could reach 86.1% and 83.3%, respectively. A new method to classify acidic and alkaline enzymes based on their sequences was established.
Amino Acids ; chemistry ; genetics ; Enzymes ; chemistry ; classification

Lipases are widely used enzymes in biotechnology. Although they catalyze the same reaction, their sequences vary. Therefore, it is highly desired to develop a fast and reliable method to identify the types of lipases according to their sequences, or even just to confirm whether they are lipases or not. By proposing two scales based pseudo amino acid composition approaches to extract the features of the sequences, a powerful predictor based on k-nearest neighbor was introduced to address the problems. The overall success rates thus obtained by the 10-fold cross-validation test were shown as below: for predicting lipases and nonlipase, the success rates were 92.8%, 91.4% and 91.3%, respectively. For lipase types, the success rates were 92.3%, 90.3% and 89.7%, respectively. Among them, the Z scales based pseudo amino acid composition was the best, T scales was the second. They outperformed significantly than 6 other frequently used sequence feature extraction methods. The high success rates yielded for such a stringent dataset indicate predicting the types of lipases is feasible and the different scales pseudo amino acid composition might be a useful tool for extracting the features of protein sequences, or at lease can play a complementary role to many of the other existing approaches.
Amino Acids ; analysis ; chemistry ; Computational Biology ; Lipase ; chemistry ; classification ; Models, Chemical ; Sequence Analysis, Protein ; methods