Further studies on thymidine kinase: distribution pattern of the enzyme in bacteria

Various micro-organisms (131 strains of 73 species) were studied for their ability to produce thymidine kinase (TK; EC 2.7.1.21). Taking the specific TK activity of Escherichia coli K12 [specific activity of sonicated cell extracts 95-194 pmol min-1 (mg protein)-1] as 100%, the test organisms had the following relative specific TK activities. In the Gram-positive cocci, Staphylococcus aureus (21-84%) showed higher activity than Staph. epidermidis (1-20%) and Streptococcus (1-7%) except for one strain of Strep. pyogenes (29%). Neisseria sicca, a Gram-negative coccus, lacked TK. Gram-positive endospore-forming rods showed significant activity (Bacillus, 13-51%; Clostridium perfringens, 9-18%) except for one strain of B. megaterium (2%) and C. difficile (1-3%). Among the Gram-positive asporogenous rods, Listeria monocytogenes and six species of Lactobacillus (especially L. brevis, L. buchneri and L. casei) had moderate to high activity (23-348%) but L. acidophilus, L. bulgaricus, L. lactis and L. cellobiosus had low activity (0-8%). Of the species of Pseudomonas studied, most lacked TK but Ps. fluorescens and Ps. maltophilia had significant TK activity (15-53%). Of the Gram-negative facultative anaerobes, Vibrio lacked TK, while Enterobacteriaceae, including Salmonella (148-1120%), Escherichia (59-141%), Klebsiella (78-299%) and Serratia (61-110%), had a high activity. Proteus had a somewhat lower activity (0-34%) except for 'Pr. rettgerella' (307%). Propionibacterium and Bifidobacterium and related organisms other than Streptomyces, Nocardia, Rhodococcus, Corynebacterium and Mycobacterium lacked TK. The seven species of Candida tested, and Cryptococcus neoformans, essentially lacked TK.(ABSTRACT TRUNCATED AT 250 WORDS)