Gene cluster for creatinine degradation in Arthrobacter sp. TE1826

The genes encoding creatininase (CrnA; 258 residues) and creatinase (CreA; 411 residues) from Arthrobacter sp. TE1826 were cloned and sequenced. The genes form a cluster with the sarcosine oxidase gene (soxA) and its regulator gene (soxR), which were cloned previously. The deduced amino acid sequences of CrnA and CreA show 35.9% and 63.1% identity, respectively to the corresponding Pseudomonas enzymes. CrnA and CreA were purified from the recombinant strains and characterized. Other open reading frames (creB and crnB), encoding proteins similar to several transporters, were found downstream of creA and crnA, respectively. Received: 15 July 1997 / Accepted: 20 October 1997     

副球菌WB1菌株肌酸酶的研究

从恒化富集培养物中分离到一株产肌酸酶的菌株WB1,通过对该菌的形态学、生理生化特性、G+C mol%及16S rDNA序列分析,表明该菌为一株副球菌(Paracoccus sp.)。对菌株WB1产酶发酵条件的研究表明,该菌除了产生肌酸酶外还产生肌氨酸脱氢酶,但不产生肌酸酐酶,也不能利用肌酸酐。肌酸酶可以被诱导物,如肌氨酸、肌酸、和氯化胆碱诱导产生。葡萄糖等易用碳源的存在对肌酸酶的合成无代谢产物阻遏作用。该酶的分子量为48kD,最适反应pH为7.0～8.5,pH稳定范围在6.0～9.5之间;其最适反应温度在35℃～40℃之间,在45℃以下是热稳定的; 37℃时以肌酸为底物,酶的Km值为24.6mmol/L;Cu2+、Hg2+和Ag+对酶活性有强烈的抑制作用。     

Simultaneous Detection of Creatine and Creatinine using a Sequential Injection Analysis/Biosensor System

Abstract

Carbon paste based biosensors for the determination of creatine and creatinine have been integrated into a sequential injection system. Applying the multi‐enzyme sequence of creatininase (CA), and/or creatinase (CI) and sarcosine oxidase (SO), hydrogen peroxide has been detected amperometrically. The linear concentration ranges are of pmol/L to nmol/L magnitude, with very low limits of detection. The proposed SIA system can be utilized reliably for the on‐line simultaneous detection of creatine and creatinine in pharmaceutical products, as well as in serum samples, with a rate of 34 samples per hour and RSD values better than 0.16% (n=10).