彈性蛋白（elastin）是由彈性纖維所構成，主要分佈於肺部，血管和皮膚的結締組織、筋、軟骨等，是人體中含量最多的不溶性蛋白，彈性蛋白酵素由於可以獨立快速的完全分解彈性蛋白（elastin），所以被稱為elastase。除了在微生物發現會分泌彈性蛋白酵素之外，在某些毒蛇的毒液中也有發現含有彈性蛋白酵素，而哺乳類動物的一些組織和細胞也會分泌，國外也有從土壤中篩選出分泌彈性蛋白酵素的菌株的報告，本實驗篩選環境中分泌彈性蛋白酵素之細菌來研究，希望能夠瞭解其細菌種類和生理特性，以及分泌酵素之條件與酵素活性方面如何。 在二十個含彈性蛋白的培養基上約300個菌落中，共篩選出六株會分泌彈性蛋白酵素之細菌，而這六株細菌都為革蘭氏陽性產內孢子桿菌，依據Bergey*s Manual of Systematic Bacteriology和A colour Atlas of Bacillus species的分類方法，鑑定這六株細菌均為Bacillus菌種，分別為Bacillus circulans E1、Bacillus pantothenticus E2、Bacillus laterosporus E3、Bacillus pumilus E4、Bacillus megaterium E5和Bacillus sphaericus E6。這六株細菌生長時的最適生長溫度是在30~40℃之間，20℃時生長十分緩慢，50℃時只有Bacillus pumilus E4能夠生長，六株細菌均為嗜中溫菌，其中菌株E1、 E 2和E3為兼性好氧菌，菌株E4 、E5和E6為好氧菌。
彈性蛋白酵素活性的測定方面，Bacillus circulans E1和Bacillus sphaericus E6分泌的彈性蛋白酵素性質相近，酵素活性受溫度和酸鹼度的影響不大。Bacillus pantothenticus E2分泌的彈性蛋白酵素，酵素活性在高溫和中性環境表現較好，在低溫和鹼性環境下活性降低很快。Bacillus laterosporus E3 和Bacillus megaterium E5分泌的彈性蛋白酵素，酵素活性在40℃和中性環境下活性最好，會依溫度和酸鹼度變化降低活性。Bacillus pumilus E4分泌的彈性蛋白酵素，酵素活性在50℃和鹼性環境下活性最好，隨著溫度和酸鹼度降低活性也降低。

Elastin is a connective tissue component of a variety of tissues and organs . In addition to constituting the major part of the intimal layer of blood vessels , it provides elasticity to lung connective tissue , yellow tendon , cartilage and skin . Elastinolytic enzymes are found in microorganisms , snake venoms , and in a number of mammalian cells and tissues , including pancreas , polymorphonuclear leukocytes , and macrophages . Elastinolytic enzymes fall into all 4 classes of proteinases (aspartic , cysteine , serine and metallo) and show a spectrum of different specificities . All elastases studied to date have catalytic activity against protein and peptide substrates other than elastin . The presence of elastase activity is a virulence factor associated with the pathogenicity of Pseudomonas and other bacteria , dermatophytic fungi , and necrosis by rattlesnake venoms .
Six strains of bacteria secreting extracellular elastase were isolated from soil and water samples . The strain E1~E6 was characterized as Bacillus circulans E1、Bacillus pantothenticus E2、Bacillus laterosporus E3、Bacillus pumilus E4、Bacillus megaterium E5 and Bacillus sphaericus E6 .
The higest amount of elastase produced by Bacillus circulans E1 and Bacillus megaterium E5 is at 30℃ , their enzyme activity at 40℃ and pH 7 is the best . The higest amount of elastase produced by Bacillus pantothenticus E2 is at 30℃ , the enzyme activity at 50℃ and pH 7 is the best . The higest amount of elastase produced by Bacillus laterosporus E3 is at 20℃ , the enzyme activity at 40℃ and pH 7 is the best . The higest amount of elastase produced by Bacillus pumilus E4 is at 40℃ , the enzyme activity at 50℃ and pH 9 is the best . The higest amount of elastase produced by Bacillus sphaericus E6 is at 40℃ , the enzyme activity at 40℃ and pH 7 is the best .

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