title: Detection of iron-porphyrin proteins with a biochemiluminescent method in search of extraterrestrial life.
abstract: Iron-porphyrin proteins (catalase, peroxidase, hemoglobin, cytochrome C) represent an important group of redoxenzymes which have vitally important functions in micro-organisms. A biochemiluminescent method was employed for the detection of iron-porphyrin proteins. The reaction of luminol oxidation with H2O2 is accompanied by chemiluminescence. The rate of hydrogen peroxide decomposition increased 10(5)-10(7) -fold in the presence of the above enzymes as compared with ferrous (or ferric) ions. Possible application of this reaction for the detection of iron-porphyrin proteins of microbial origin was studied. Other authors have suggested this reaction for the detection of extraterrestrial life. Kinetics of the above reaction in the presence of iron-porphyrin proteins were shown to differ both in amplitude and duration of the signal from the pattern observed in the presence of non-hemin catalysts. The reaction pattern in the presence of mixed-soil populations is similar to those observed with pure bacterial cultures and individual iron-porphyrin proteins. Photometric tests revealed that among preparations studied the addition of 0.01% lysozyme was the most effective in destroying cell walls in microbial populations. However, removal of cell walls is not a necessary prerequisite for the detection of iron porphyrin since, for effective luminol oxidation with H2O2 the medium should be kept at pH 12.0. Pretreatment of microbial suspensions with ultrasound increased 2-fold the total signal due to iron porphyrins. The above method gives a reproducible signal indicating the presence of iron porphyrins when sterile nutrient media were innoculated with desert soil samples (Repeteck, Kara-Kum) and incubated for 13 hr. The device was able to detect the presence of no less than 10(5) - 10(6) cells per ml. The addition of limonite (Fe2O3 X nH2O) does not result in the appearance of an appreciable signal in the luminol + H2O2 system.
authors.affiliation: Academy of Sciences, Moscow, USSR.
authors.forename: G G
authors.initials: GG
authors.lastname: Sotnikov
mesh_terms: D001410:Bacillus megaterium / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism; D003889:Desert Climate; D004926:Escherichia coli / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism; D018559:Exobiology; D006420:Hemeproteins / Q000032:analysis* / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000737:chemistry / Q000493:pharmacokinetics; D007501:Iron / Q000494:pharmacology; D008163:Luminescent Measurements; D008165:Luminol / Q000737:chemistry / Q000493:pharmacokinetics; D010544:Peroxidases / Q000032:analysis* / Q000378:metabolism; D012988:Soil Microbiology
chemical_list: D006420:Hemeproteins; D008165:Luminol; D006861:Hydrogen Peroxide; D007501:Iron; D010544:Peroxidases