Literature summary extracted from

Ladero, M.; Santos, A.; Garcia, J.L.; Carrascosa, A.V.; Pessela, B.C.C.; Garcia-Ochoa, F.
Studies on the activity and the stability of beta-galactosidases from Thermus sp. strain T2 and from Kluyveromyces fragilis (2002), Enzyme Microb. Technol., 30, 392-405.

No PubMed abstract available

General Stability

EC Number	General Stability	Organism
3.2.1.23	10% inactivation after 4 h in 40% tetraglyme, 20% inactivation after 4 h in 70% tetraglyme, 50% inactivation after 4 h in 80% tetraglyme	Kluyveromyces marxianus
3.2.1.23	15% inactivation after 4 h in 40% triethyl phosphate, 45% inactivation after 4 h in 50% triethyl phosphate, 52% inactivation after 4 h in 60% triethyl phosphate, 67% inactivation after 4 h in 70% triethyl phosphate, 85% inactivation after 4 h in 80% triethyl phosphate	Thermus sp.
3.2.1.23	20% inactivation after 4 h in 40% triethyl phosphate, 42% inactivation after 4 h in 50% triethyl phosphate, 53% inactivation after 4 h in 60% triethyl phosphate, 64% inactivation after 4 h in 70% triethyl phosphate, 82% inactivation after 4 h in 80% triethyl phosphate	Kluyveromyces marxianus
3.2.1.23	25% inactivation after 10 h in 0.8% Tween 80 in Tris-HCl buffer	Thermus sp.
3.2.1.23	5% inactivation after 4 h in 60% tetraglyme, 35% inactivation after 4 h in 80% tetraglyme	Thermus sp.
3.2.1.23	50% inactivation after 10 h in 5% SDS in Tris-HCl buffer	Thermus sp.
3.2.1.23	87% inactivation after 10 h in 0.5% SDS in Tris-HCl buffer	Kluyveromyces marxianus
3.2.1.23	unstable in 0.2 M urea	Kluyveromyces marxianus

Inhibitors

EC Number	Inhibitors	Comment	Organism	Structure
3.2.1.23	Co2+	0.1 mM, 88% inhibition	Thermus sp.
3.2.1.23	Cu2+	0.1 mM, 55% inhibition	Thermus sp.
3.2.1.23	Mn2+	0.1 mM, 90% inhibition	Thermus sp.
3.2.1.23	SDS	0.5 mM, 87% inactivation	Kluyveromyces marxianus
3.2.1.23	SDS	1 mM, complete inactivation	Thermus sp.
3.2.1.23	Tween 80	0.5% in Tris-HCl, 25% inactivation	Thermus sp.

Metals/Ions

EC Number	Metals/Ions	Comment	Organism	Structure
3.2.1.23	Al3+	0.1 mM, activation to 118% of initial activity	Kluyveromyces marxianus
3.2.1.23	Co2+	0.1 mM, activation to 124% of initial activity	Kluyveromyces marxianus
3.2.1.23	Mn2+	0.1 mM, activation to 120% of initial activity	Kluyveromyces marxianus
3.2.1.23	Ni2+	0.1 mM, activation to 118% of initial activity	Kluyveromyces marxianus

Molecular Weight [Da]

EC Number	Molecular Weight [Da]	Molecular Weight Maximum [Da]	Comment	Organism
3.2.1.23	140000	-	dimer, gel filtration	Thermus sp.
3.2.1.23	200000	-	dimer, gel filtration	Kluyveromyces marxianus
3.2.1.23	550000	-	octamer, gel filtration	Thermus sp.

Organic Solvent Stability

EC Number	Organic Solvent	Comment	Organism
3.2.1.23	Ethanol	5% inactivation after 4 h in 20% ethanol, 65% inactivation after 4 h in 40% ethanol, complete inactivation after 4 h in 60% ethanol	Kluyveromyces marxianus
3.2.1.23	Ethanol	5% inactivation after 4 h in 20% ethanol, 82% inactivation after 4 h in 60% ethanol	Thermus sp.

Organism

EC Number	Organism	UniProt	Comment	Textmining
3.2.1.23	Kluyveromyces marxianus	-	-	-
3.2.1.23	Thermus sp.	-	-	-

Oxidation Stability

EC Number	Oxidation Stability	Organism
3.2.1.23	0.6% v/v H2O2 is very deleterious to the activity of the thermophilic enzyme	Thermus sp.
3.2.1.23	0.6% v/v H2O2 sarcely affects the enzyme	Kluyveromyces marxianus

Purification (Commentary)

EC Number	Purification (Comment)	Organism
3.2.1.23	partial	Kluyveromyces marxianus
3.2.1.23	partial	Thermus sp.

Substrates and Products (Substrate)

EC Number	Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
3.2.1.23	lactose + H2O	-	Kluyveromyces marxianus	D-glucose + D-galactose	-	?
3.2.1.23	lactose + H2O	-	Thermus sp.	D-glucose + D-galactose	-	?
3.2.1.23	additional information	enzyme shows a remarkably hydrolytic activity and a weak transgalactosylation activity, even in the presence of high concentrations of lactose, production of Gal-Gal and Gal-Gal-Glu	Kluyveromyces marxianus	?	-	?
3.2.1.23	additional information	enzyme shows a remarkably hydrolytic activity and a weak transgalactosylation activity, even in the presence of high concentrations of lactose, production of Gal-Gal-Glu	Thermus sp.	?	-	?
3.2.1.23	o-nitrophenyl beta-D-galactopyranoside + H2O	-	Kluyveromyces marxianus	o-nitrophenol + beta-D-galactose	-	?
3.2.1.23	o-nitrophenyl beta-D-galactopyranoside + H2O	-	Thermus sp.	o-nitrophenol + beta-D-galactose	-	?
3.2.1.23	p-nitrophenyl beta-D-galactopyranoside + H2O	-	Kluyveromyces marxianus	p-nitrophenol + beta-D-galactose	-	?
3.2.1.23	p-nitrophenyl beta-D-galactopyranoside + H2O	-	Thermus sp.	p-nitrophenol + beta-D-galactose	-	?

Subunits

EC Number	Subunits	Comment	Organism
3.2.1.23	dimer	-	Kluyveromyces marxianus

Temperature Stability [°C]

EC Number	Temperature Stability Minimum [°C]	Temperature Stability Maximum [°C]	Comment	Organism
3.2.1.23	25	-	about 30% loss of activity after 55 h	Kluyveromyces marxianus
3.2.1.23	40	-	about 30% loss of activity after 5 h, about 75% loss of activity after 33 h	Kluyveromyces marxianus
3.2.1.23	45	-	about 60% loss of activity after 5 h, about 90% loss of activity after 25 h	Kluyveromyces marxianus
3.2.1.23	50	-	about 90% loss of activity after 2 hm complete inactivation agter 5 h	Kluyveromyces marxianus
3.2.1.23	60	-	about 20% loss of activity after 20 h	Thermus sp.
3.2.1.23	70	-	about 45% loss of activity after 20 h	Thermus sp.
3.2.1.23	80	-	6 h, stable	Thermus sp.
3.2.1.23	90	-	1 h, stable	Thermus sp.

pH Optimum

EC Number	pH Optimum Minimum	pH Optimum Maximum	Comment	Organism
3.2.1.23	5	-	hydrolysis of o-nitrophenyl beta-D-galactopyranoside	Thermus sp.
3.2.1.23	6.5	-	hydrolysis of lactose	Thermus sp.
3.2.1.23	6.5	6.8	hydrolysis of lactose or o-nitrophenyl beta-D-galactopyranoside	Kluyveromyces marxianus

pH Stability

EC Number	pH Stability	pH Stability Maximum	Comment	Organism
3.2.1.23	1	2	70°C, about 30% loss of activity after 10 min, about 50% loss of activity after 1 h, about 75% loss of activity after 3 h	Thermus sp.
3.2.1.23	4	-	70°C, about 20% loss of activity after 10 min, about 40% loss of activity after 1 h, about 75%loss of activity after 2 h, about 90% loss of activity after 3 h	Thermus sp.
3.2.1.23	4	-	about 20% loss of activity after 10 min, about 85% loss of activity after 3 h	Kluyveromyces marxianus
3.2.1.23	5	-	about 25% loss of activity after 1 h, about 60% of maximal activity after 3 h	Kluyveromyces marxianus
3.2.1.23	6	10	70°C, 3 h, stable	Thermus sp.
3.2.1.23	6	-	about 20% loss of activity after 3 h	Kluyveromyces marxianus
3.2.1.23	7	-	about 5% loss of activity after 3 h	Kluyveromyces marxianus
3.2.1.23	8	-	about 5% loss of activity after 3 h	Kluyveromyces marxianus
3.2.1.23	9	-	about 35% loss of activity after 1 h, about 75% loss of activity after 3 h	Kluyveromyces marxianus
3.2.1.23	10	-	about 65% loss of activity after 10 in, about 90% loss of activity after 1 h	Kluyveromyces marxianus

Ki Value [mM]

EC Number	Ki Value [mM]	Ki Value maximum [mM]	Inhibitor	Comment	Organism	Structure
3.2.1.23	0.14	-	Cu2+	70°C	Thermus sp.
3.2.1.23	1.85	-	Co2+	70°C	Thermus sp.
3.2.1.23	9.23	-	Mn2+	70°C	Thermus sp.

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Release 2023.1 (January 2023)