[Radiochemical transformation of glycyl-containing peptides]. / Radiatsionno-khimicheskie prevrashcheniia nekotorykh glitsilsoderzhashchikh peptidov.

The effect of gamma-radiation on aqueous peptide solutions containing amino acids characteristic of collagen (for instance, diglycyl-glycine, glycyl-tyrosine, and prolyl-glycine) has been investigated. A radiochemical yield of the disintegration of amino acid residues of these peptides and breakage of the glycyl-tyrosine peptide bond due to OH. and e-aq has been determined. Aspartic acid has been shown to form upon radiolysis of oxygen free diglycyl-glycine solutions and its yield has been determined.

[Changes in the secondary structure of collagen after gamma-irradiation in an aqueous solution]. / Izmenenie vtorichnoi struktury kollagena pri gamma-obluchenii v vodnom rastvore.

The conformation of calf skin collagen at the secondary structure level changed after 60Co-gamma-radiation with doses ranging from 50 to 1,000 Gy in aerated aqueous solutions and in the presence of N2 and N2O. Despiralization of collagen at a dose of 1,000 Gy reached 90% in N2O, 70% in N2, and 60% in the aerated solution. The radiochemical yield of the despiralized collagen molecules was 0.007 mol/100 eV owing to OH(.). The presence of radioprotective agents upon irradiation of collagen solutions diminished considerably the injury to its secondary structure.

[Characteristics of the effect of gamma-irradiation on the amino acid composition of collagen as modified by a gaseous atmosphere]. / Ob osobennostiakh deistviia gamma-izlucheniia na aminokislotnyi sostav kollagena pri modifitsiruiushchem vliianii gazovoi atmosfery.

The comparative changes in the amino acid composition of calf skin collagen after gamma-irradiation (doses from 100 to 1,000 Gy) in aqueous solutions under different gas atmospheres (O2, N2O, H2, vacuum) were investigated. The radiochemical yields of collagen amino acid residues destruction were determined. Under O2 (OH X, O2-) most of amino acids are destroyed with higher yields than under N2O. Leucine, valine, isoleucine, phenylalanine, arginine were the exception because of their high reaction rate constants with OH X and hydroxylation reactions. Under H2 (e-aq, H) and in vacuum (e-aq, OH X) the mechanism of collagen radiolysis changed due to its aggregation; the destruction of those amino acids which have high reaction rate constants with water radiolysis products was mainly observed (phenylalanine, tyrosine, histidine).

[Changes in the collagen amino acid composition of calf skin after gamma-irradiation in an aqueous solution]. / Izmenenie aminokislotnogo sostava kollagena kozhi telenka pri gamma-obluchenii v vodnom rastvore.

A study was made of the amino acid composition of calf skin collagen after gamma-irradiation (60Co) of 2.5 X 10(-6) M aerated aqueous protein solution within the dose range from 30 to 2000 Gy. The radiosensitivity of amino acid residues was compared.