• Applied Biological Chemistry
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• 제40권3호
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• pp.196-201
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• 1997

Lysine 특이적 serine protease인 Achromobacter protease I(API)의 기질특이성을 결정하는 아미노산 잔기가 255위치에 존재하는 가정하에 이 잔가에 변이를 도입하여 기질특이성의 변화 유무를 조사하였다. 그리고 pro-API이 자기촉매적으로 소화될 수 있도록 Lys(-1) 또는 다른 아미노산 잔기로 치환하였다. 그러나 예상과는 달리 제작된 모든 변이체는 발현되지 않았거나 불활성전구체로서 발현되었다. 이 결과로부터 225위치의 잔기는 API의 maturation과정에 있어 Iysylendopeptidase활성에 중요한 역할을 담당하고 있으나 APl의 기질특이성은 225위치 잔기의 특성에 한정되지 않을 가능성이 시사되었다.

• 약학회지
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• 제37권6호
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• pp.571-576
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• 1993

The substrate specificity of the purified rabbit plasma alkaline phosphatase (ALPase) was determined towards a extended range of potential substrates including relatively simple phosphate derivatives as p-NPP and indolyl phosphate, and several synthetic peptides and phosphoproteins. These results further estabilish the broad substrate specificity of these circulating enzymes. Interestingly, the plasma ALPase preferentially dephosphorylates Thr over Ser residues, as demonstrated with a series of synthetic peptides. The latter result is in contradiction to the behaviour of the tissue ALPase, which is thought to the ultimate source of plasma ALPase, and open therefore new perspectives with respective to the origin and "solubilisation" processes of these enzymes. Dephsphrylation of protein substrates by endogenous and isolated plasma ALPases indicates that ALPase probably displays protein phosphatase activity in vivo.

• Journal of Microbiology and Biotechnology
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• 제32권7호
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• pp.949-954
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• 2022

The lipolytic yeast Candida aaseri SH14 contains three Acyl-CoA oxidases (ACOXs) which are encoded by the CaAOX2, CaAOX4, and CaAOX5 genes and catalyze the first reaction in the β-oxidation of fatty acids. Here, the respective functions of the three CaAOX isozymes were studied by growth analysis of mutant strains constructed by a combination of three CaAOX mutations in minimal medium containing fatty acid as the sole carbon source. Substrate specificity of the CaAOX isozymes was analyzed using recombinant C. aaseri SH14 strains overexpressing the respective genes. CaAOX2 isozyme showed substrate specificity toward short- and medium-chain fatty acids (C6-C12), while CaAOX5 isozyme preferred long-chain fatty acid longer than C12. CaAOX4 isozyme revealed a preference for a broad substrate spectrum from C6-C16. Although the substrate specificity of CaAOX2 and CaAOX5 covers medium- and long-chain fatty acids, these two isozymes were insufficient for complete β-oxidation of long-chain fatty acids, and therefore CaAOX4 was indispensable.

• Journal of Microbiology and Biotechnology
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• 제11권5호
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• pp.798-803
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• 2001

Peptide synthetases produced from various microorganisms are multifunctional enzyme complexes and their substrates are recognized and activated by adenylation domains. To identify the substrate specificity of the peptide synthetase isolated from Bacillus subtilis 713, known to produce an antifungal peptide, two adenylation domains containing the minimal functional portion were expressed and purified. ATP-ppi exchange experiments and kinetic studies revealed that the two adenylation enzymes had a substrate specificity to $_{L}-lysine{\;}and{\;}_{L}-tryptophan$, respectively. In addition, based on a signature sequence comparison, the substrate of the third domain was predicted to be L-glutamic acid. These results suggest that this peptide synthetase is novel because there has been no previous report on a peptide synthetase that uses $_{L}-lysine,{\;}_{L}-tryptophan,{\;}and{\;}_{L}-glutamic$ acid as substrates in that order.

• Journal of Microbiology and Biotechnology
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• 제25권12호
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• pp.2024-2033
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• 2015

A gene encoding lipolytic enzyme, lip7-3, was isolated from Bacillus sp. W130-35 isolated from a tidal mud flat. The gene encoded a protein of 215 amino acids with a signal peptide composed of 34 amino acid residues. Lip7-3 belonged to the family I.4 lipase and showed its maximal activity at pH 9.0 and 60℃. Its activity increased in the presence of 30% methanol and, remarkably, increased as well to 154.6% in the presence of Ca²⁺. Lip7-3 preferred p-nitrophenyl octanoate (C8) as a substrate and exhibited broad specificity for short- to long- chain fatty acid esters. Additionally, Lip7-3 showed a low degree of enantioselectivity for an S-enantiomer (e.g., (S)-methyl-3-hydroxy-2-methylpropionate). It efficiently hydrolyzed glyceryl tributyrate, but did not hydrolyze glyceryl trioleate, fish oil, or olive oil. Its substrate specificity and activation by the solvent might offer a merit to the biotechnological enzyme applications like transesterification in the production of biodiesel.

• Journal of Microbiology and Biotechnology
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• 제13권1호
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• pp.57-63
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• 2003

Using fungal (Fusarium solani f. pisi) and bacterial (Pseudomonas mendocina) cutinases, the initial hydrolysis rate of p-nitrophenyl esters was systematically estimated for a wide range of enzyme and substrate concentrations using a 96-well microplate reader. Both cutinases exhibited a high substrate specificity; i.e. a high hydrolytic activity on p-nitrophenyl butyrate (PNB), yet extremely low activity on p-nitrophenyl palmitate (PNP). When compared to the hydrolysis of PNB and PNP by other hydrolases [lipases and esterases derived from different microbial sources, such as bacteria (Pseudomonas cepacia, Psedomonas furescens, Baciilus stearothermophilus), molds (Aspeillus niger, mucor miehei), and yeasts (Candida rugosa, Candida cylindracea)], the above substrate specificity would seem to be a unique characteristic of cutinases. Secondly, the hydrolytic activity of the cutinases on PNB appeared much faster than that of the other hydrolytic enzymes mentioned above. Furthermore, the current study proved that even when the cutinases were mixed with large amounts of other hydrolases (lipases or esterases), the Initial hydrolysis rate of PNB was determined only by the cutinase concentration for each PNB concentration. This property of cutinase activity would seem to result from a higher accessibility to the substrate PNB, compared with the other hydrolytic enzymes. Accordingly, these distinct properties of cutinases may be very useful in the rapid and easy isolation of various natural cutinases with different microbial sources, each of which may provide a novel industrial application with a specific enzymatic function.

• BMB Reports
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• 제37권6호
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• pp.642-647
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• 2004

The lysine residues of Bacillus licheniformis $\alpha$-amylase (BLA) were chemically modified using citraconic anhydride or succinic anhydride. Modification caused fundamental changes in the enzymes specificity, as indicated by a dramatic increase in maltosidase and a reduction in amylase activity. These changes in substrate specificity were found to coincide with a change in the cleavage pattern of the substrates and with a conversion of the native endo- form of the enzyme to a modified exo- form. Progressive increases in the productions of $\rho$-nitrophenol or glucose, when para nitrophenyl-maltoheptaoside or soluble starch, respectively, was used as substrate, were observed upon modification. The described changes were affected by the size of incorporated modified reagent: citraconic anhydride was more effective than succinic anhydride. Reasons for the observed changes are discussed and reasons for the effectivenesses of chemical modifications for tailoring enzyme specificities are suggested.

• Bulletin of the Korean Chemical Society
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• 제17권10호
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• pp.905-908
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• 1996

A substrate specificity of cabbage phospholipase D (PLD) was studied using the synthetic phospholipids having different head groups. The phospholipids were synthesized from phosphatidylcholine and appropriate bases by transphosphatidylation of PLD. The bases used were ethanolamine, serine, ethanol and γ-hydroxybutyric acid. The phosphatidic acid, the product of PLD, was separated in TLC and measured densitometrically. The kinetic parameters were estimated for each substrate and the effects of pH, SDS, Ca2+ and other metal ions were examined. Vmax values found were 3.75, 2.36, 5.59, 1.63, 2.30 nmol/min/μg protein for phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidylethanol, and phosphatidylburytic acid, respectively. These results indicate a broad specificity of cabbage PLD toward phospholipids with different head groups. Particularly phosphatidylserine was most easily hydrolyzed by PLD and its activity did not depend on Ca2+.

• 약학회지
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• 제41권4호
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• pp.530-532
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• 1997

The MICs of various macrolide, lincosamide and streptogramin B antibiotics against highly erythromycin-resistant Escherichia coli 209K strain were evaluated. E. coli 209K showed high MICs against 14-membered macrolides and the relatively weaker resistance to 16-membered macrolides, lincosamides and streptogramin B. The macrolide-phosphotransferase K from E. coli 209K showed greater substrate specificity to the 14-membered macrolide antibiotics than to the 16-membered macrolide antibiotics, lincosamide and streptogramin B. Therefore, it was considered that the high resistance was due to the macrolide-phosphotransferase K.

• BMB Reports
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• 제53권12호
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• pp.611-621
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• 2020

Bacterial endoribonuclease toxins belong to a protein family that inhibits bacterial growth by degrading mRNA or rRNA sequences. The toxin genes are organized in pairs with its cognate antitoxins in the chromosome and thus the activities of the toxins are antagonized by antitoxin proteins or RNAs during active translation. In response to a variety of cellular stresses, the endoribonuclease toxins appear to be released from antitoxin molecules via proteolytic cleavage of antitoxin proteins or preferential degradation of antitoxin RNAs and cleave a diverse range of mRNA or rRNA sequences in a sequence-specific or codon-specific manner, resulting in various biological phenomena such as antibiotic tolerance and persister cell formation. Given that substrate specificity of each endoribonuclease toxin is determined by its structure and the composition of active site residues, we summarize the biology, structure, and substrate specificity of the updated bacterial endoribonuclease toxins.